Obtaining water from your hot water heater

In a grid down sit­u­a­tion where water ser­vice is inter­rupt­ed or oth­er­wise is in short sup­ply, you will still need a source of clean water for drink­ing, cook­ing, bathing etc. If you live in a small home or have some oth­er stor­age issues for large amounts of portable water, you may have to look at uncon­ven­tion­al sources. The top tank of your toi­lets are one such source; the tank is clean, fresh water and has not been con­t­a­m­i­nat­ed like the water in the bowl has been with human waste (how­ev­er, do NOT use toi­let tank water if you have treat­ed the tank with a chem­i­cal that makes clean­ing the bowl eas­i­er). Anoth­er much larg­er source is your water heater and the steps below will teach you how to safe­ly obtain this water. This is assum­ing, of course, you don’t have a tan­k­less water heater; in that case you can still emp­ty the lines of your home of exist­ing water but you will only be able to get a small amount com­pared to the 30–50 gal­lons you will be able to obtain from a water heater (depend­ing on the size of the tank). Fol­low the steps below and you will have a rather large source of potable water.

1. Turn off the water sup­ply to your house so that you can cap­ture all the clean water in the pipes with lit­tle fear of con­t­a­m­i­na­tion from taint­ed water from the com­mu­ni­ty ser­vice lines.

2. Turn off the water heater (if its a gas water heater its best to turn off the gas sup­ply to the heater for safe­ty rea­sons).

3. Allow the water to cool; depend­ing on the size of the water heater, this could take sev­er­al hours. A way to ver­i­fy the water is safe to touch is to open the pres­sure release valve into a buck­et and cau­tious­ly check the water tem­per­a­ture in the buck­et.

4. Option­al: Screw a shut­off valve onto the drain valve of the water heater. This isnt nec­es­sary but depend­ing on the water heater valve, can make the process eas­i­er (and safer). Screw a short length of hose to the end of the valve if it is too low to get a buck­et or bowl under­neath.

5. Open the drain valve into a clean buck­et or large bowl to col­lect clean, potable water (note that the bucket/bowl need not be clean if you plan on puri­fy­ing the water after with bleach or by boil­ing). The water won’t flow well from the water heater because of the vac­u­um cre­at­ed by open­ing the low­est point of a closed sys­tem (think of a full 2 liter soda bot­tle held upside down). Pri­or to open­ing the water heater valve, you can open a faucet at the high­est point of the house to alle­vi­ate this vac­u­um effect or, a much better/easier idea, you can use the pres­sure relief valve on the water heater.

6. When you’re done, close the valve on the water heater (or the back­up valve you’ve installed).

You may hear gur­gling sounds in the water lines in your house after emp­ty­ing water from a water heater. This is total­ly nor­mal, air is mak­ing its way through the lines (to the high­est point in the sys­tem). When/if water ser­vice is recon­nect­ed to the house, you will prob­a­bly have air com­ing out of your faucets for a short time as the sys­tem refills with water… again per­fect­ly nor­mal.