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Baby, it’s cold out. How to protect your rainwater harvesting system from freezing temperatures.

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The record freezing temperature across the country can cause real problems with rainwater harvesting systems.  Areas accustom to mild temperature each winter are scrabbling to prevent broken pipes and indoor flooding.  Rainwater harvesting systems installed in mild climates are in danger of experiencing these same issues. Precautions or contingency measures need to be taken to prevent freeze damage.


Since The Original Rainwater Pillow is so easily customized to fit just about any space, most are being installed in conditioned areas.  With this type of installation, the only concern is that all the water in the pipes exposed to the cold must drain completely into the pillow.


The Original Rainwater Pillow is build with material that can withstand -31 degrees F.

Unfortunately, pipes and pumps  connected to the pillow cannot be allowed to freeze and will need protection.



In cold weather climates, many pillows are simply drained until mild temperatures arrive in March.  This is a simple way to handle freezing temperatures if you are only harvesting rainwater for irrigation.  


When shutting down the RWH system is not an option, then the system design needs to eliminate freeze damage potential.  Here are a few ideas to get you through a short duration of freezing events.


Insulation is the first line of defense. A large volume of water will need to be exposed to below freezing temperatures over a long period of time in order for the water to freeze solid. Destruction of pipes or pumps is only caused when the water inside freezes completely.  Your pipes are most vulnerable because they contain a small volume of water which freezes quickly.  The amount of insulation required depends on how cold it gets and the duration.


A second step is to circulate the water with the pump continuously throughout the freezing period.  Even slow moving water will prevent a solid freeze.  This is a short term solution but can protect your rainwater harvesting system while keeping all the water in your tank.  


Lastly, the water can be heated as is often done in remote cold locations.  Various options are available including solar, propane, and electricity.  These are expensive options over a long term period but excellent for short durations of freezing.  Pipes also need to be either heated separately or have a continuous flow of water with a small pump.


A freeze prevention plan must be included in the design phase of a rainwater harvesting system.  A well designed system means less maintenance which is always better.


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