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Winterizing Guide: How to Freeze-Protect Water Supply Piping, Drain Piping, Water Pumps, Tanks, Heaters PlumbingAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• How to winterize or freezeproof a building - how to set the down thermostat or turn off heat entirely
• How to avoid freezing water supply pipes and drain piping, drains, traps, toilets, etc.
• How to winterize pipes: frost protection for plumbing systems
• Use of heat tapes, heat sources, pipe routing, to prevent freezing pipes
• How to thaw frozen water pipes, heating pipes, & drain pipes
• How to fix frozen, burst, leaky building pipes
• How to de-winterize a building and restore it to service: check for & fix leaks, set up water equipment.

The articles at this website will answer most questions about freeze protection for piping and other building plumbing and heating system components: how to winterize a building to avoid frozen pipes, and how to thaw frozen water supply & drain piping, wells, & water tanks.

A Detailed Guide to Winterizing a Building to Protect from Frozen Pipes, Leaks, Water Damage

What happens when water freezes in a copper pipe?

Our separated copper pipe solder joint (above left) shows how freeze damage to a heating system baseboard pipe can cause the copper pipe to simply slip apart at the solder joint. Our freeze-bulged and split copper water pipe (above right) shows how a copper water pipe can freeze, expand, and burst.

The resultant building water flooding and damage can be extensive and in some cases may involve a costly mold remediation project as well. Also, failure of an owner to take appropriate steps to prevent freezing pipes and water damage can result in loss of insurance coverage in some instances. For example, turning off heat without also winterizing a home would be an improper practice likely to lead to frozen burst pipes and water damage and mold contamination.

Our photo at left shows a separated solder joint caused by freezing at a heating baseboard copper pipe. The repair of this leak is shown later in this article.

Our page top photo shows a frozen, burst water pipe close to an elbow. We suspect that the process of heating the pipe during soldering of the elbow connection might soften the copper in this location, permitting the very rounded expansion shape at the point of pipe rupture. The elbow itself may be more resistant to bursting during freezing.

Reproduction of this web page electronically at other websites is prohibited. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

Text in process August 2008 - Contact Us with questions or text suggestions.

Key Building Winterizing Topics to Avoid Freeze Damage

Freezing water pipes or drain pipes in a building are worse than inconvenient: often the frozen pipes burst, risking serious water damage and even toxic mold growth in a building when the frozen, burst pipe later thaws and leaks into the structure. The most extreme water and mold damage to buildings where pipes burst occurs in unoccupied structures whose conditions are not being monitored, such as a house for sale, or a remote, weekend home. Other freezing weather damage besides floods from frozen pipes can include cracked plaster in older homes or cracked and dislocated wood flooring.

For buildings facing these extra risks, we provide a range of suggestions for winterizing or freeze-proofing a building as well as for monitoring building conditions so that prompt action can be taken to deal with a burst pipe.

Here is our list of key topics to consider when working to winterize or freeze-proof a building, along with links to more detail on these subjects:

1. Prepare the building to be left unattended: regardless of whether heat is to be left on or off:

• Turn off unneeded electrical components. Modern TV's and items that use plug-in wall chargers and voltage converters are always using electricity. Unplug sensitive electronic equipment to protect against power surges or lightning.
• Protect against rodents and animal damage: close openings into soffits, attics, basements, crawl spaces; be sure all trash and garbage have been removed from the building. Raccoons used to play with the Christmas ornaments in our attic, and mice would come into the building to eat anything, even books and bars of soap.
  
  How we keep mice our of our building: It's almost impossible to keep mice out of a building if they want to come in for the winter (they do). Beyond calling for regular visits from a pest control expert, here is what we recommend>
  
  Removing any open food, storing food in cans or closed heavy plastic containers, and closing obvious mouse entry points will help. Our attorney ignored these suggestions and was plagued with mice, tolerating them until the morning that bleary-eyed, hardly awake, she was pouring rice crispies into her cereal bowl. A mouse lept out of the box right into her cereal!
  
  We leave mothballs (naphta) in areas and even in equipment that tends to be invaded by pests looking for a sheltered place to spend the winter. Mothballs keep mice out of the filing cabinets in our unheated garage. Just put the whole box of mothballs, opened, but not poured out, into the cabinet, closet, or vehicle.
• Insurance coverage: review your building insurance policy with your agent to be sure the property is covered when it is unoccupied.
• Windows and doors: make sure that all windows are closed. If the building has triple-track storm and screen windows, make sure that the storm windows are closed with the glass "down" - not just the screens down. Latch and lock these openings.
• Other building button-up details: Make sure building exhaust fans are off. If the building has an exhaust fan that leaks or blows cold air in or leaks warm air out, cover the opening (remember to remove those covers before use to avoid a fire risk.) Stop mail and magazine or newspaper deliveries. Let a trusted neighbor know you'll be away and ask them to keep an eye on the property.
• Building winterizing & monitoring services: decide if you want or need a professional to winterize your building and or to monitor it during the time that it will be shut down.in some locales companies offer a winterized building protection service that ranges from weekly or even daily visits to check on a property to emergency response to a no-heat call or water-entry call that can be made automatically by a home security system when those conditions occur. If power outages are common in the area, a battery-backup for alarms and sump pumps would be a smart addition to the building.

2. Decide if the building heat going to be left "on" or "off" : the answer determines the type and extent of freeze-proofing steps needed.

• If heat is to be left on in a partially winterized building see the procedure at: Winterize - Heat On
• If heat is to be turned off and the building completely winterized, see the procedure at: Winterize- Heat Off

Below we list topics of special interest for people who are leaving a building unattended in freezing weather.

Frozen hot water heating baseboards & radiators: how to prevent this problem which leads to loss of heat and more extensive freeze and later water damage to buildings. Our photo just shows a frozen, burst hot water baseboard heating pipe. If a building heating system shuts down due to an operating problem (loss of electricity, a problem with the heater itself, or simply due to running out of oil) the heating system failure is likely to lead to frozen pipes which, when the weather warms, can cause serious building flooding and water or mold damage. A burst heating baseboard line such as the ones we show here and at the top of this page can occur at more than one point in the heating system piping. See our Heat-On Winterizing Guide.

• Leaks and burst frozen pipe repairs - how to quickly find and repair frost-damaged piping, avoiding water damage and mold contamination due to frozen burst piping are discussed in a detailed procedure at De-Winterized a Building.

• Restoring a winterized building to service: what to turn on first, how to watch for hidden freeze-damage to piping, mechanical systems, appliances, and fixtures are discussed in a detailed procedure at De-Winterized a Building.

• Thawing frozen pipes: how to un-freeze pipes, how to find where the pipes are frozen, how to avoid setting the building on fire is discussed in detail at Thawing Frozen Pipes.

• Thermostat set-back guide to avoid freezing pipes in buildings: how to find the optimum low-temperature setting for a building thermostat is discussed in detail at Thermostat Settings.

• Water Softener & Treatment Equipment winterization an freeze-proof recommendations

• Water turn off for freeze protection: where to turn off building water, what water to leave on, how to safely leave hot water heat on with other water shut off. Draining water tanks, water pumps, hot water tanks.

• Winterizing steps to take in a building - winterizing or freeze-protection for building water supply piping, turning off water, preventing freezing pipes, draining piping systems, shutting down a building entirely: draining piping, turning off heat and electricity.

• Winterizing other building equipment: heating systems, water tanks & pumps, toilets, drain traps are discussed at Winterize- Heat Off.

How to Winterize a building to Prevent Freeze Damage

First we decide the level of building winterization to be undertaken. There are two very different approaches to protecting a building and its mechanical systems from freezing-damage:

1. Heat-on winterization: the first approach to winterizing a building involves keeping the building heated, but to a lower temperature. This approach is usually best for a building as it helps avoid indoor humidity, moisture, and even freeze-cracking of some building materials such as flooring or drywall. We discuss "Heat-On" building winterization steps at How to Winterize a Building If you are Keeping Heat On.
2. Heat-off winterization: the second approach to winterizing a building is to turn off its heat, often also its electricity, drain piping, and take other steps to reduce the chances of freeze-damage. This approach is taken when a building is to be left unoccupied for a long time, when the owners cannot pay for heat (though they may face later repairs that would have made the heating cost look attractive), or when a building has been abandoned, such as a foreclosed property. We discuss "Heat-Off" building winterization steps at How to Winterize a Building If you are Turning Building Heat Off.
   

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

FREEZE-PROOF A BUILDING
Key Winterizing Topics
How to Winterize a Building

Winterize - Heat On Procedure
  Thermostat Settings
  Turn Water Off ?
  Winterize Water Softener & Treatment Equip.
  Find & Fix Water Pipe Freeze-Up Points
  Heat tapes, Heat, Insulation prevent Freeze-Up
  Freeze Protect Drains

Winterize- Heat Off Procedure

De-Winterized a Building
  Thawing Frozen Pipes
  Repairing Burst Leaky Pipes
  Turning on Heating
  Restoring Drains
  Turning on Water
  Water Supply/Drain Pipe Leak Types
  Restoring Water Softener & Treatment Equip

Technical Reviewers & References

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

• Daniel Friedman - principal author/editor of the InspectAPedia ^TM Website
• "New Electric Heat Tapes Help Prevent Fires," US Consumer Product Safety Commission (CPSC) #00936
• Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• "Freezeproof Your House," Mike McClintock, Rodale's New Shelter, p. 30, October 1985 (approximate date)
• "How to Winterize Your Pipes," Mike McClintock, Homeowners How-To Magazine, p. 59-62, Nov-Dec 1979.
• Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

More expert information on this topic

How to Winterize a Building If you are Keeping Heat On

The simple steps to winterizing a building where heat is being left on include choosing a low setting for the heating thermostat, turning off all or portions of the water supply piping, locating and correcting points of extra risk of freezing, and possibly the installation of a freeze-alarm notification system.

Thermostat Settings to Avoid Freezing

Find the lowest "safe" temperature for setting the thermostat. In theory we simply need to keep the building just above 32 degF. But actually dropping a building interior temperature down that low is risky. Why? Because often there is some cold corner, under a sink cabinet, or in a drafty basement corner, where temperatures can fall far below the number set on the building thermostat. So we need to keep the building temperature at the thermostat high enough that the coldest spot in the building where piping may be exposed to freezing will remain warm enough. Other building corners can get a bit colder if the do not contain anything in danger of freeze damage.

Safe temperature unknown: 55 to 50 degF: If you have no experience with how a particular building behaves in freezing weather, it's smart to start by keeping the temperatures pretty high. It's usually "safe" to drop a thermostat to 55 degF. or even down to 50 degF (though below we also offer a few simple extra things you can do to avoid freeze-ups).

Even hot pipes can freeze: Beware, in unusual cases even a hot water heating line can freeze-up. A client had recurrent freeze-ups of his hot water heating baseboard piping (where the circulating water can be 180 degF !). We found a very cold drafty corner in a crawl space where freezing winter air was blowing right across an elbow in the hot water heating baseboard piping. When the building thermostat decided that the living space was warm enough and thus turned off the heating boiler and circulator, this cold corner would freeze in very cold windy weather. The solution was simple: block the draft and insulate the corner. (Continuous operating hot water circulation as a freeze-protection method is discussed below).

How to Find the Safe Set-back Temperature for a Heating Thermostat: It's easy to do a little experimenting to find out just how low you can safely set building temperature without freezing anything if the building is occupied or if the building can be checked regularly. To start we set the thermostat down to 55 deg. F, remembering that the thermostat is only monitoring the room temperature at the precise spot where it is located. So other building locations may be warmer or colder. We watch what happens in areas of the building distant from the thermostat and possibly exposed to colder conditions.

We find the coldest point where plumbing or other freeze-protected components are located. That's the temperature that we monitor as we step the thermostat lower and lower.

• We need to actually measure temperatures around the building after outdoor temperatures have been at their low point for several hours.
  
• We can also double check that all of our plumbing fixtures are still working. It's often the case that a water line will freeze enough to reduce or stop water flow before it freezes hard enough to burst the line. So if we're checking frequently and find that suddenly our water supply has stopped, we need to immediately turn the heat up (high, to warm the building quickly) and then to proceed to locate to point at which the water pipe has frozen. As we related anecdotally above, in many buildings we can locate and correct one or two problem locations that will then let us set the building temperature lower without freeze-damage.

40 deg .F. Using this approach it may be possible to drop a building interior temperature to 40 degF. without freeze damage occurring.

How to set a thermostat below it's official minimum temperature: if your building thermostat is an older model that does not permit temperatures to be set below 50 or 55 deg .f. it may be possible to "fool" the thermostat by tilting it out of level on the wall, so that a setting of "55 degF" on the thermostat dial is really equivalent to "45 degF". A little experimenting (at a higher temperature) will show you how much to turn the thermostat on the wall to re-set its operating temperature range. See THERMOSTATS.

Why we like to keep some heat on: Even in a building with no plumbing to freeze up, it's usually better for the building to keep some heat going at this level than to allow it to reach zero or sub-zero temperatures. You may find that allowing a building to reach very cold temperatures can result in movement of building materials or cracking damage such as to flooring or even wall materials. In some locations there may also be a risk of elevated indoor humidity leading to mold contamination even if the building piping is not leaking.

Now that we've agreed to leave some heat on, it is still important to find freeze-risk points and to take some steps to avoid freeze damage by turning off water where we can, adding point heat sources, fixing drafts, etc. An experienced home inspector and some heating contractors or insulation contractors can probably point out spots where there is an extra risk of freezing pipes.

Guide to Turning off Water to a Winterized Building

Not ok to turn off water: But if the building is heated by a system that requires water, such as a steam boiler or a hot water (hydronic) heating boiler, turning off the building water supply can risk serious damage or total destruction to the heating boiler or even unsafe conditions. That's because most heating systems that use water rely on the presence of an automatic water feed valve to assure that makeup water is sent into the heating boiler whenever its water level drops below a safe level.

What can we do to protect a building from frozen burst pipes and later flooding if heat is provided by a hot water heating system?

1. Go ahead and turn off the water: some hydronic heating boilers do not normally consume water; on occasion we see that the building winterizing procedure has included simply "taking a chance" and turning off the water. If you know the boiler's behavior well and know that there are no leaks in the hot water heating system you might feel that the risk of boiler damage due to running out of water is low. Of course should a leak in the heating system develop when no one is at home, the boiler can be damaged, ruined, or the loss of heat (when the boiler stops working) can cause other freeze damage.
2. Turn off all water into the building except for a dedicated water supply line feeding the heating boiler: we prefer this solution. You may need to ask a plumber to make a small adjustment to the water supply piping, to provide a direct water feed line to the heating boiler, but with the installation of a main water shutoff valve that will shut off all other water supply piping in the building. Certainly if the building uses steam heat (which always consumes or loses some water during normal operation) you will want to use this option.
3. Leave the main water supply valve on but turn off all other water supply shutoff valves in the building except for piping that feeds the heating boiler. Be sure that your water supply piping has been mapped carefully. Often one can simply install an additional shutoff valve or two to turn off all water other than piping feeding the heating boiler.
4. In the hot water heating boiler, use an anti-freeze mix intended for use in hot water heating system boilers (not a steam boiler, we're referring instead to hot water baseboard or hot water radiator heating systems).

See Water Feeder Valves, Hydronic Boiler and Low Water Cutoff Controls for more discussion of heating boiler water control valves.

What about leaving water running slowly to avoid frozen pipes. This is a last resort measure which we don't like. Not only are we wasting water, we risk flooding a septic system, or we risk freezing the building drain lines by the slow flow of water. In emergency however, such as loss of heat during a winter storm, this step could be necessary and would make sense.

How to Winterize a Water Softener or other Water Treatment Equipment

Even if you are leaving heat turned on in an unoccupied building during winter, it still makes sense to turn off the water softener:

1. No one is using any water, so it does not need to regenerate itself, and if you leave the water softener operating, if it's like most "dumb" water softeners that recharge themselves based on a simple clock mechanism, you're wasting water, salt, and energy.
   
   If your water softener is a model that actually monitors water usage and water hardness, it should not be running itself through a regenerating cycle when the building is empty - no one is using any water. Still we can protect the equipment and the building from a possible leak by turning it off.
2. There is the risk of a cold-weather caused or other malfunction or a frozen pipe that could flood the building when the water softener is back-washing and re-charging itself.
3. Freeze risk in the salt tank may be low: a water softener, because it's tank is salty, probably has a lower freeze point in the salt tank itself, but still the softener body water pipes feeding it could freeze and break.

Take these two water softener winterizing steps if you are leaving heat on:

When the building is reoccupied, you'll need to take these steps to get your water softener working again. Those steps are detailed at Restoring Water Treatment Equipment - How do We Return the Water Softener to Operation & Use at the End of Winter?

More information about the use of water softeners is at Water Softener Operation & Maintenance.

Guide to Finding and Correcting Freeze-Up Risk Points in Buildings

You can do a lot to correct a freezing pipe problem in a building that is exposed to cold weather. Even in an occupied building pipes can freeze in some conditions. Here are some examples of places to look for freezing trouble and what to do about them:

Water pipes (both supply & drain) & hot water heating pipes or steam heat condensate pipes or building drains routed through un-heated areas or passing by areas exposed to cold drafts. Check piping that runs along or near the building sills or building perimeter in basements, crawl spaces, attics. Check water supply piping and horizontal drain lines and fixture traps in cold areas where building heat does not easily enter, such as the pipe chase at left. Often you can simply cut an opening to let warm air enter such spots.

• Look for drafts: On a cold, windy day, explore your home, especially the un-heated areas such as where pipes pass along or close to the building perimeter sills or foundation top in basements or crawl spaces. If the building has sections of floor that overhang lower parts of the building (such as a raised ranch) be sure the floor under-side is well-insulated and thoroughly sealed against drafts. When cold wind blows against a home which has an overhanging floor, wind against the building can force cold air into the wall cavity or even up into the building walls through a poorly-sealed under-side of the overhanging floor.
  
  Explore the building on a cold windy day, looking for drafts: feel for cold drafts that blow on water piping or heating piping. Fix those drafts and you'll significantly reduce the chances of a frozen pipe. Fixing a draft means adding caulking, a plastic air barrier, using foam insulation, or other means to block un-wanted air flow into a building.
• Look for places where pipes touch un-heated surfaces, such as foundation surfaces or framing. These may conduct heat away from the pipe and speed freezing at that point.
• Look for the coldest of the un-heated areas where pipes run, such as an un-insulated attic, a pipe chase in a building corner, a crawl space (especially near foundation vents or other drafty spots), or as we explained just above, in a raised-ranch type home, where pipes run in the section of an upper floor which overhangs the building foundation (and may be poorly insulated).

Look for evidence that pipes have frozen before, and find out why the freeze occurred in that spot. You may see a bulged pipe that didn't burst (if it burst it would have leaked and been repaired), or you may see a section of piping with one or even several pipe couplings soldered in place, a likely indicator that that section of piping has frozen before. In our photo at left you can see that freezing has damaged the heating baseboard pipe and a copper pipe coupling has been used to make a repair by replacing a damaged section.

Plumbing fixtures in un-heated areas such as a bathroom or kitchen sink in a room that does not have its own heat source; in kitchens and bathrooms we may leave open vanity cabinet doors to permit warmer building air to reach pipes in those areas.

How & Where to add Heat to Protect Plumbing Pipes or Components from Freezing

Adding heat to protect plumbing in un-heated areas such as crawl spaces: you may add heat either by installing a short section of heating baseboard, an extra opening cut in a warm air supply duct running through a crawl area, a small thermostatically-controlled electric heater set to operate only at low temperatures, or in small but cold areas, a simple light bulb may provide enough heat to prevent freezing.

Check these auxiliary heaters frequently to assure that the heat source is still working; be sure to respect fire safety when installing any heat source. Adding small point-sources of extra heat in a building to protect from freezing is likely to be more economical than running the central heating system to a higher temperature just to warm up a cold corner or two. Particularly if the thermostat set-back temperature results in the heating system turning on less often, adding point source heating may be needed.

We can add heat to protect plumbing and heating piping using any of the methods listed below and described in detail in this article:

• Increase the flow of warm building air from the heated space into the cold corner or spot at risk of freezing by cutting one or more openings that let air circulate into the cold spot. In some bathrooms or kitchens we may simply leave the cabinet doors open to let room air reach sink plumbing.
• Add a point-source of heat such as a tiny low-temperature-on electric heater, a short section of hot water heating baseboard, or by cutting an extra opening to let warm air blow out of a warm air supply duct into the cold area
• Use heat tapes on piping in areas which are difficult to heat
• Use a light bulb as a heat source
• Add insulation on piping to protect it from freezing
• Change heating system controls to continuously circulate the water inside of heating baseboards or radiators even when the boiler is not itself heating the water.
• Leave water faucets open to a drip or very slow trickle: this is an emergency procedure that you may need to use if your building loses heat. Normally it's not a great idea to leave water running as we are wasting water, risking frozen drain lines, and if a septic system is installed, we risk flooding the septic system.

Increase warm air flow: Another way we've added heat to problem areas where pipes freeze is to simply make one or more openings to permit warm air to circulate from the building into the cold area. After finding freezing water pipes entering a bathroom located over a kitchen in a home with warm air heat, we cut an opening in the kitchen ceiling and installed a heating register there to make the hole look nice. Warm air rising from the kitchen proved sufficient to prevent a future freeze-up of the pipes in that location.

In any cold area where you are adding heat to avoid freezing pipes, the amount of heat you need to add will be reduced a lot if the cold area itself is insulated. Fiberglass insulation is fine for most building locations, but to reduce the risk of mold growth, we prefer to use solid foam insulation in areas like crawl spaces that are exposed to dampness.

Guide to Using Heat Tapes to Protect Pipes From Freezing

Common locations where heating tapes are used on plumbing to prevent freezing pipes include:

• Water pipes run through attics
• Water pipes run through un-heated crawl spaces
• Water pipes and equipment in un-heated garages
• Water equipment in well pits
• Water pipes running under porches

Some older or less costly models of heating tapes present a fire risk, particularly if the heating tape is crossed over itself. Be sure to read the product specifications, safety warnings, and installation guide before installing a heating tape on building piping of any kind.

Pipe Heat Tape Safety Guide from the US CPSC

The U.S. CPSC has provided safety recommendations for homeowners using heat tapes to help prevent fires: Replace heat tapes that are older than three years Use only heat tapes certified to meet recognized voluntary fire safety standards such as those provided by Underwriters Laboratories (UL), the Canadian Standards Association (CSA), and the Factory Mutual Research Corporation (FMRC). Plug the grounded (3-prong) plug into a grounded GFCI (ground-fault circuit interrupter) protected electrical outlet Don't cross the heat tape across itself unless the manufacturer says that's acceptable - crossed heat tapes can overheat and start a fire Put the heating tape on the surface of the pipe to be protected from freezing, not on top of pipe insulation, and do not cover the heating tape with insulation unless the manufacturer says that's acceptable. Use only non-combustible insulation on pipes where heating tapes are installed (like fiberglass insulation). Foam or vinyl pipe insulation may catch on fire from a faulty heat tape or faulty heat tape installation. Protect the sealed end-cap of the heat tape (see our photo above) from damage and water leaks which could cause a short circuit or fire. Use heating tape only for the application approved for that particular heating tape, such as for use on piping. Some heat tapes are designed for use in gutters or driveways while others are designed for use on piping or fuel piping. Be sure that the heat tape thermostat (if one is provided) is placed where the instructions say. For example some heat tape thermostats should be placed in contact with the pipe, others left hanging in air. (See our photo above) Replace any heat tape that is discolored (a sign of overheating), cracked, melted, or damaged in any way.

Guide to Pipe Insulation to Prevent Freezing

Plastic piping to resist freezing: modern plastic piping is considerably more tolerant of freezing without bursting than copper or steel water pipes. In a home intended for regular winterization some builders use exclusively plastic pipes to resist freeze damage. Be careful: even when freeze-tolerant piping is used, the piping connections, elbows, unions, couplings, and plumbing fixtures are still at risk of frost damage.

How to Avoid Freeze Damage to Building Drain Piping

Such drains can easily freeze in an un-heated home, leading to broken drain lines, frost-heaved basement floors, and severe basement flooding.

We recommend that drain connections between roof gutters and downspouts and the building sewer line be abandoned. If necessary, install temporary above-ground downspout extensions to conduct roof runoff well away from the building rather than into the sewer line via the basement floor. Incidentally, because the volume of roof runoff sent into a sewer line can overwhelm municipal sewage treatment plants this connection is prohibited in some communities.

How to Winterize a Building If you are Turning the Heat Off

If you have decided to shut down the building's heating system, some steps to protect the building from freeze damage are simple (you don't worry about figuring out the thermostat set-temperature nor about finding "cold spots" where pipes may freeze). But other critical steps need to be performed:

1. Close the main building water supply valve. Check that the valve really closed fully during the process of draining the piping. Be careful: some valves that are seldom used or which are old may not close off completely. You just think you've turned off the water supply, but really your water main valve may still be slowly feeding water back into the supply piping.
2. If a water pump and pressure tank are installed, turn off electrical power to the water pump. (Draining the pump and water tank are discussed below.)
3. Drain the building water supply piping; because most homes other than some vacation cottages are not built with piping intended to be periodically drained, there may be long horizontal pipe runs that will not easily drain out all of their water by gravity, or even some supply pipes that slope "backwards" and refuse to drain.
   1. Use air to remove water: Some plumbers try blowing air through the piping to force out water, or they may install multiple points at which piping can be drained. Below we address some steps to check for frozen, burst piping when turning the water supply back on.
   2. Cut pipes to remove water: Other plumbers will simply cut open any water supply pipe that may not be draining properly, figuring that it's a much smaller repair to later close that cut connection than to fix a building that has been flooded.
   3. Use the building drain: Most buildings include a building drain valve located at or near the lowest point in the building supply piping, but "inside" the building or past the main building water supply shutoff valve.
4. Drain the building plumbing fixtures, tanks, faucets, such as
   1. Winterize toilets, and remove all toilet water from bowls and toilet tanks. Some winterizing companies pour an anti-freeze mix into building toilets and traps. Some anti-freeze chemicals are toxic and should not be discharged into a septic system. See notes below about use of antifreeze in buildings.
   2. Winterize water heaters (never turn on electricity to a drained electric water heater, nor turn on power to a gas or oil fired water heater either - it is dangerous and is likely to destroy the heater too)
   3. Winterize well water tanks and pumps: need to be completely drained of water - a frozen burst in-building water pump adds an expensive repair later
   4. Winterize all building faucets: after water supply has been turned off, open every faucet and leave it open - water left in a faucet can freeze and break it.
   5. Open outdoor faucets: be sure also to remove any garden hoses on outside faucets. A garden hose can retain water that freezes and damages the outdoor hose bib (faucet).
   6. Turn off and drain the water softener or other water treatment equipment. See details at Winterize Water Softener & Treatment Equip.
5. Empty or remove building fixture traps; see our note below about use of antifreeze.
6. Use of antifreeze to winterize a building: Be careful: unless the anti-freeze is specifically designed for winterizing a building it could be highly toxic (such as automobile antifreeze). We do not recommend using toxic antifreeze to winterize a building since later you're moving that contaminant into the public sewer or into soils (and possibly ground water) around a private septic system. Only inside of closed water systems such as a heating boiler do we recommend use of anti-freeze mix in a building.

7. Drain the hot water tank and other building tanks: the hot water tank and water pressure tank and pump itself if a private well and tank system are installed. This sketch of a gas-fired water heater and its control valves is provided courtesy of Carson Dunlop. Warning: do not drain a water heater tank before first turning off its energy source: oil, gas, or electricity. Heating an empty water tank is very dangerous and is likely to quickly destroy the tank or its heating elements. Also see Winterize Water Softener & Treatment Equip. - about turning off water softeners and, if heat is to be turned off, drain the softener and any other water treatment equipment.

8. Shut down the heating system when all other steps to protect the building have been completed:
   1. Hot water heating systems: Drain the building heating boiler and heating supply piping, or install an anti-freeze mix in the heating boiler and its supply piping. Notify your oil heat supplier if you are turning off heat in the building, and remember to notify them again when it is turned back on.
   2. Steam heating systems: drain the heating boiler and condensate lines and condensate pump if a pump or pumping station are used.
   3. Electric heat or warm air furnaces: can simply be turned off.

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FREEZE-PROOF A BUILDING
Key Winterizing Topics
How to Winterize a Building
Winterize - Heat On Procedure
  Thermostat Settings
  Turn Water Off ?
  Winterize Water Softener & Treatment Equip.
  Find & Fix Water Pipe Freeze-Up Points
  Heat tapes, Heat, Insulation prevent Freeze-Up
  Freeze Protect Drains
Winterize- Heat Off Procedure
De-Winterized a Building
  Thawing Frozen Pipes
  Repairing Burst Leaky Pipes
  Turning on Heating
  Restoring Drains
  Turning on Water
  Water Supply/Drain Pipe Leak Types
  Restoring Water Softener & Treatment Equip

Technical Reviewers & References

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

• Daniel Friedman - principal author/editor of the InspectAPedia ^TM Website
• "New Electric Heat Tapes Help Prevent Fires," US Consumer Product Safety Commission (CPSC) #00936
• Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• "Houses in Hibernation," Steve Bailey, New York Times, 24 October 2008 p. D2.
• "Freezeproof Your House," Mike McClintock, Rodale's New Shelter, p. 30, October 1985 (approximate date)
• "How to Winterize Your Pipes," Mike McClintock, Homeowners How-To Magazine, p. 59-62, Nov-Dec 1979.
• Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

More expert information on this topic

More Information about Plumbing and General Building or Home Inspections

• Clogged Drain Diagnosis: Is it a blocked drain or the septic system? - A First Step for Homeowners
• DRAIN NOISE DIAGNOSIS: may indicate defective or clogged plumbing: how to diagnose and cure drain sounds
• Guide to Heating Thermostats - how to install, adjust, set thermostats - avoid freezing pipes
• Heating Boiler Operation Details - 39 steps: keep the heat working to avoid freezing pipes
• Heat loss diagnosis: for hot water systems (boilers) and for warm air systems (furnaces)
• HOT WATER HEATERS - a detailed guide to all types of hot water sources, problems, inspection, repair
• Water Pressure Loss - Diagnosis how to determine why water pressure has been lost or why there is no water at all in a building

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