How do I flush a toilet when the power or water is out?

Sort that out first, because it decides everything else.

A regular tank toilet flushes by gravity. Flushmate, a maker of pressure-assist systems, describes gravity-fed toilets as designed to siphon waste out of the bowl. Nothing in that needs electricity.

Pressure-assist toilets (the loud ones) use your water line instead. Flushmate says its 1.0 gallon model needs line pressure of 35 psi or greater, and its 1.6 and 1.28 gallon models need 20 psi or greater. If the water is weak or off, they cannot recharge. Follow the maker's outage procedure; do not pour water into the pressure vessel.

An electric flush mechanism may have a manual backup, but its model manual decides the procedure. A macerating or upflush toilet relies on an electric waste pump: stop using it when that pump has no power. Do not keep adding water to its storage chamber. See how an upflush toilet works.

For an ordinary gravity toilet with intact drainage, bucket water can trigger a flush without line pressure. The steps are short, but the speed and the amount of water both matter.

1. 1Fill a bucket with water. It doesn't need to be drinkable, so save your drinking water for drinking. Pima County's emergency guidance says you may use bath, laundry or pool water.
2. 2Pour into the bowl steadily enough to start a flush, watching the water level. Stop immediately if it rises toward the rim; bucket water will not clear a blocked drain.
3. 3After a successful flush, restore the bowl's normal standing water so its trap provides a barrier to sewer gas.
4. 4Keep a filled bucket by the toilet so the next flush is quick, and refill it when it's empty.

### How much water do you pour to flush a toilet?

Here's what the sources say, and why the numbers differ.

Pima County, Arizona says: "If there is no water in your toilet, but the sewer lines are intact, pour 3-5 gallons of water into the toilet bowl to flush." This is emergency guidance, not the normal flush-volume rating of every toilet.

For water reserved for drinking, see choosing and maintaining emergency drinking-water containers; toilet-flushing water has a different purpose.

The EPA says WaterSense-labeled toilets use 1.28 gallons per flush or less in normal operation, while some older toilets use as much as 6 gallons. Those ratings describe the installed flush system. They do not certify a universal bucket-flush volume; use the model instructions where available and never add water to a backing-up bowl.

### Can you fill the tank instead?

Yes. The Virginia Department of Health says: "Toilets can be flushed by pouring a bucketful of water either into the tank and using the handle, or by pouring a bucketful into the bowl." Filling the tank lets the toilet flush the way it was built to. Pour toward the water line marked inside the tank, then press the handle.

These alternatives are for compatible gravity toilets. Do not refill a cracked tank.

Ask why the water is out before you flush anything.

### What if a water line might be broken?

Be careful. Pima County says: "If you suspect damage to your home's water lines, do NOT flush the toilet." It says to turn off the water at the house so contaminated water doesn't enter your water system. Pima says the shutoff is usually where the water line enters the home, and turns clockwise to close.

If the outage came with a boil-water notice, see what to do during a boil-water notice. If only some taps are dry, no water from your faucets covers the checks.

### What if you can't flush at all?

Sometimes the sewer side is the problem. Pima says that if sewer lines are broken, you line the toilet bowl with double-bagged garbage bags instead of flushing. Before discarding a bag, Pima says to add a small amount of bleach, seal it, and keep it in a tightly covered container away from people. If the toilet is unusable, its guidance is a sturdy bucket with a tight-fitting lid, lined with a double-bagged plastic garbage bag.

The Washington State Department of Health describes the same setup and adds steps. Turn the toilet's water valve off, and flush out any water still in the bowl. Line the bowl with one bag inside another, and put kitty litter, peat moss, lime or something similar in the inner bag to absorb liquid and reduce odors. Store used bags away from kids, pets and wildlife. Wash your hands with soap and running water, and use wet wipes or sanitizer if you have no running water. Its first option is simply to use a neighbor's, friend's or local business's toilet if one is working.

APS says monsoon storms can cause outages, and that they "can and do occur." Whether your taps keep running through one depends on your water supplier, and this page can't tell you that for your street. If your water goes dry or weak, use the pour method above.

Homes on a private well are the sure exception. The Virginia Department of Health says a well pump won't work when power goes out, so plan on pouring. See well water system basics. It adds that septic systems with a pump won't work without power either. Most should have 100 to 200 gallons of storage above the high-level alarm, and it advises using water sparingly. Read more in how monsoon season affects plumbing.

One easy prep move: fill the bathtub or a couple of buckets before a storm you can see coming. Pima lists bath water as usable for flushing.

Once water and drainage are restored, follow the model's restart guidance and check that the tank refills and shuts off. If a toilet will not refill, leaks or overflows after an outage, HQ Plumbing & Air offers 24/7 emergency service and is licensed and insured.