Emergency Water Sources

 Even without emergency water storage, you should be aware of some potential emergency water sources that are often overlooked. These emergency water sources in your home are not sufficient for even a short term solution, but, depending on the number of people in your home and your actions in the event of an emergency, they could give you a day or more of water.

In an emergency situation, the ideal is to shut off your water main to prevent any contaminated water from infiltrating your home water system.

Shutting off the water main should keep outside, possibly contaminated, water from entering into your home's system. Because it is possible your home's water could have become tainted, it's never a bad idea to boil the water before you drink or use it for cooking.

You can access water from a few different “emergency water sources” in your home. Some are ready-to-drink and other sources need to be treated before using. Two possible ready-to-drink sources are from the water pipes and the water heater tank. I say “possible” because it’s also possible contaminated water from the main could have also contaminated your home’s water system.

Other emergency water sources should be treated, filtered and disinfected, before use. These include toilet tanks, pools, and other water sources such as rainwater, streams, ponds, lakes, or springs.

water pouring

Emergency Water Source- Water Pipes

Unless your pipes drain after every use, your water pipes should be an emergency water source. Even turning off the water main, there will still be some water in the pipes...until they're drained, which is what your goal is.

To access the emergency water remaining in your home’s pipes, you basically get one chance.

In a multi-level home, open one faucet on the highest level. You may want to place a container (like a pot or bowl) under it to catch any wayward drips, but the primary purpose of opening this faucet is to let air into the system. Then go to the lowest faucet of the home, place a container under it and open the faucet.  Turn it off before the container gets too full.

In a single-level home, there may be a faucet that is a little higher or lower than others. Often the bathtub will be the lowest faucet, and kitchen sinks are higher than bathroom sinks. Sometimes the washing machine water hook-up is highest. But, if you can’t identify the highest and lowest faucets, put containers under each and have someone help you turn the faucets on and off.

Emergency Water Source - Water Heater

In the event of an emergency, many houses have a built-in emergency water storage: the hot water heater tank. Remember, small tanks are usually 30-40 gallons, while larger tanks are 50 or more. With the recommended water storage minimum of 1 gallon per person per day, a small 30-gallon tank could last awhile. But, you need to be careful how you access the water and to not lose any.

Here’s how to access the emergency water source in a water heater.

You will need to turn the heater off. Even if a power or gas outage has already shut it off, it’s good to make sure the water heater is off. For electric water heaters, shut off the water heater’s circuit breaker. On gas water heaters, turn the thermostat down and rotate the gas supply knob to the off position.

You should let the water in the tank cool down before you attempt to access it. You don’t want to get scalded from hot water. Because water heaters are generally insulated, you should let it cool off for a few hours.

When you’re ready to get water from the tank, shut-off the water supply going into the tank. The shut-off valve will likely be a quarter-turn ball valve, or a gate valve which needs to be turned several times to shut-off the supply. Since your water main should already be off, this is more to preserve the cleanliness of the water in the tank as contaminated water may come through the lines at first when water service is restored. It can also help prevent siphoning of contaminated water into the tank when you start draining it.

At the bottom of the tank there should be a drain valve. Many look like a threaded connector that you can hook a garden hose to, and that’s basically what you need to do. You don’t need a long hose, and most garden hoses are not sanitary enough to use with drinking water. But, a convenient hose of about the right length is one of the water hoses for your washer. Turn off the washer’s water valve and remove the hose. Then thread the hose onto the drain “faucet” of the water tank. The best option is a potable/drinking water hose (often colored blue), but keep the washer hose as an emergency option.

If the drain valve does not have an ordinary handle, but a slot where a handle could attach, you could use a screwdriver or coin to rotate the slot.

Be careful, and work slowly when trying to open the drain valve. These are seldom used (maybe once a year if you get your water heater serviced) and will likely be difficult to open. You don’t want to end up breaking or damaging the valve.

If you’ve opened the valve, most likely you’ll find very little water coming out. In order for the tank to drain, you will also need to allow air into it. This is easily done by turning on any hot water faucet in the house. This allows air into the pipes, and back into the tank. You will probably hear some strange sucking-like sounds as water drains into your container.

Be aware that sediment does collect at the bottom of the tank. This is typical mineral sediment found in your drinking water. If there is sediment, just allow it to settle to the bottom of your container.

If your tank uses an aluminum anode you may find a jelly-like aluminum corrosion by-product on the tank bottom. Don’t drink that.

While the water should be safe to drink (after all, from the water heater it goes to the rest of the home), it wouldn’t hurt to boil or filter it before drinking.

Something you may consider doing before an emergency is to replace the factory drain valve with a ball-valve. Ball-valves allow for a straight water flow and are less likely to get clogged up by hard water sediments like a gate valve might. Ball-valves are also much easier to turn should someone lacking strength need to access the water.

An important note: be sure to refill the water tank before you turn the water heater back on. 

Emergency Water Sources - Other

Where the water in the pipes and water heater should be safe to drink, particularly if you shut off the water main, there are other emergency water sources that should be treated before you drink or use for cooking.

Toilet Tank

First, this is the water in the tank and not the bowl. If you don’t add any cleaning chemicals to the tank this water could be utilized, after being filtered and disinfected. While this water comes directly from the water pipes, the tank itself is usually not clean enough for drinking. If you add any chemicals to the tank, the water is definitely unsafe and only use it for non-internal use, meaning don’t drink it, and don’t use if for cooking or for personal hygiene.


There were several times during our years in Chile when the water supply was either contaminated or had failed. Thankfully my parents kept water storage so we had water for drinking and cooking. 

In our backyard we also had a pool. It was an in-ground pool and Dad kept water in it year-round. Not because we swam in it all year but because he said it was better for it in the event of an earthquake. We did have a fence around it to keep us kids out when we weren't allowed in the pool area.


Whenever there was a water outage, we would get buckets of water from the pool to take to the bathrooms. We’d then use this water to flush the toilets. It’s a surprise to some people, but the water system does not need to be running for the sewer to work. The water drains use gravity, so you can flush toilets by dumping water into them.

However, be aware that in an earthquake the sewer lines could be damaged and prevent proper flow. Most likely there won’t be enough usage of the sewage system for this to be noticed, but it is a real possibility that things won’t drain as expected and could back up easier.

Back to the pool.

Besides using the water for sanitary purposes, if we ever needed to, we could have also filtered it and boiled it for drinking. 

Temperatures were mild enough where we lived (meaning it rarely got below freezing) that we kept water in the pool year-round. This doesn’t mean it was always treated and clean enough for swimming, only that we had water in it. Springtime usually came with a serious pool cleaning.

If you live in a temperate climate, you might consider leaving water in your pool. However, leaving water in an above ground pool year-round is not advisable.

Rainwater Collection

Rainwater collection is more of potential source of water than a water storage solution. The problem is not knowing when rain is coming. However, if you have a rainwater collection system there may be water you can treat and disinfect for other uses.

I’m considering the creation of a rainwater collection system, mostly to catch water from our roof so I could use it on the garden. I plan to modify the rain gutter downspouts to run into a series of barrels, which could then be siphoned to the garden beds. I won’t go into details as there are a wide variety of systems that could be built. 

You should also be aware that in some areas there are actually laws that govern rainwater collection. Yes, it sounds crazy but there are places where it’s illegal to collect rainwater. In some places it may be frowned upon, while in others it might be encouraged. It’s in your best interest to check your local regulations.

This type of system would be very valuable if you are in a post-disaster situation and need an additional source of water for other needs, such as a garden.

Other Emergency Water Sources

As mentioned earlier, there is a small river near our home. It will be convenient if it’s still running after a natural disaster, but I’m not counting on it. And there are a lot of people upstream from us, so there may not be much water left, and it may be very contaminated. There is a lake a couple miles away, but its distance and occasional algal bloom problems make it an unreliable source.

Before the time of an emergency, consider what your other sources of water might be, such as:
  • Rainwater
  • Rivers, streams, or other sources of moving water.
  • Lakes and ponds.
  • Natural springs.

Also, be aware of some cautions.
  • Don’t use water that has an odor, is dark colored, or has floating material (like oil).
  • Don’t drink flood water.
  • Don’t use saltwater unless you distill it first.

Some more information from the CDC Making Water Safe in an Emergency


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