well water during a power outage — how to keep water flowing

If you're on well water and the power goes out, you don't just lose your lights. You lose your water. All of it. No faucets, no toilets, no showers, no washing dishes, no filling the dog bowl. Nothing comes out of any tap in your house until the electricity comes back or you find another way to run that pump.

I know this because I live on well water. I have lived through outages where the power was gone for three days and the only thing standing between my family and a genuinely miserable situation was preparation I'd done months earlier. Water is the thing that separates "inconvenient outage" from "emergency" faster than anything else. You can eat peanut butter by flashlight. You cannot go two days without water.

This guide covers why your well stops, how long you actually have, every option for getting water during an outage, and how to prepare so you never have to find out what happens when you run dry.

why your well water stops when the power goes out

Unlike city water, which is pressurized by the municipal system and usually keeps flowing during outages, well water depends entirely on an electric pump sitting at the bottom of your well. Most modern residential wells use a submersible pump — a sealed unit lowered 100 to 400 feet underground, connected to your house by a pipe and a power cable.

When electricity reaches the pump, it pushes water up the pipe, through a check valve, and into your pressure tank. The pressure tank is a steel or fiberglass tank (usually in your basement or utility room) that stores water under pressure. When you open a faucet, the pressure in the tank pushes water through your pipes. When the pressure drops to a set point, the pressure switch tells the pump to kick on and refill the tank.

No electricity. No pump. No new water in the tank. Once the tank empties, nothing comes out of any faucet anywhere in your house.

It's that simple and that absolute. There is no backup built into the system. There is no reserve. The entire water supply for your household — drinking, cooking, bathing, flushing toilets, laundry, everything — depends on a single electric motor at the bottom of a hole in your yard.

how long your pressure tank lasts

Your pressure tank is the only water you have when the power goes out. How long it lasts depends on two things: how big the tank is and how fast you use water.

Most residential pressure tanks fall into three sizes:

• Small (20 gallons). Common in older homes and smaller systems. Usable water is roughly 5-7 gallons — the rest is air pressure.
• Standard (30-44 gallons). The most common residential size. Usable water is about 10-15 gallons.
• Large (80+ gallons). Less common, but some homes have them. Usable water is 25-35 gallons.

Here's the problem: a single toilet flush uses 1.6 gallons. A one-minute hand wash uses 1-2 gallons. A five-minute shower uses 10-15 gallons. A dishwasher cycle uses 6 gallons. A load of laundry uses 15-30 gallons.

If you have a standard 30-gallon pressure tank with about 12 gallons of usable water and a family of four, and someone flushes a toilet twice and washes their hands three times, you've used roughly 7 gallons. A single shower empties the tank. Two toilet flushes and some hand-washing gets you uncomfortably close to empty.

If you know an outage is coming — a storm warning, a planned utility shutdown — stop using water immediately. Every gallon in that tank is precious. Don't run the dishwasher. Don't do laundry. Don't take showers. Conserve what's in the tank for drinking and essential sanitation only.

Better yet: if you get advance warning, fill every container you own. Bathtubs, pots, buckets, water jugs. Your bathtub alone holds 40-80 gallons. That water won't be pressurized, but you can use it for flushing toilets by pouring a bucket directly into the bowl.

option 1: generator powering the well pump

This is the most practical solution for most people. A generator provides electricity, the electricity runs your pump, and your water system works normally. Faucets flow. Toilets flush. Life continues.

But there's a critical detail that trips people up: startup surge.

Your well pump might run at 1,000 watts, but when it first kicks on, it draws 2-4 times that amount for a few seconds. A 1/2 HP submersible pump runs at about 1,000 watts but surges to 2,000-3,000 watts. A 1 HP pump runs at about 2,000 watts but surges to 4,000-6,000 watts. If your generator can't handle the surge, the pump won't start. The generator will either trip its breaker or stall.

This means you need to size your generator for the surge, not the running watts. A 4,000-watt generator handles most 1/2 HP and 3/4 HP well pumps comfortably. For a 1 HP pump, you want at least 5,000-6,000 watts of peak capacity.

I've written a detailed breakdown at best generator for well pump, including specific models and how to match them to your pump. If you don't know your pump's horsepower, check the label on the pressure switch or control box near your pressure tank — it should list the HP and voltage.

how to connect a generator to your well pump

You have two options:

• Transfer switch (recommended). An electrician installs a transfer switch on your electrical panel. During an outage, you plug the generator into a dedicated inlet, flip the transfer switch, and your well pump (plus whatever other circuits you've selected) runs off the generator. Safe, legal, and you can power the pump without running extension cords. Cost: $300-800 installed.
• Direct wiring (not recommended for most people). Some people wire a generator directly to their well pump circuit. This is technically possible but requires electrical knowledge, proper disconnects, and carries real risk of backfeeding the grid, which can kill a lineworker. If you don't know what you're doing, get a transfer switch.

You don't need to run the generator continuously. Run it for 20-30 minutes to fill the pressure tank, then shut it down. The tank holds enough water for several hours of conservative use. Run the generator again when the pressure drops. This stretches your fuel dramatically.

For more on portable generators, see best portable generators.

option 2: hand pump for shallow wells

If your well is under 200 feet deep, a hand pump is a viable permanent backup that requires no electricity, no fuel, and no maintenance beyond occasional seal replacement. You pump a handle, water comes up. It's the technology that kept humanity alive for centuries and it still works.

Two brands dominate the residential hand pump market:

• Simple Pump. Made in the USA. Works on wells up to 325 feet (with effort at that depth). Can be installed alongside your existing submersible pump in the same well casing. Stainless steel construction. Costs $1,200-2,000 depending on depth and configuration. This is the gold standard.
• Bison Pumps. Also American-made. Similar concept, works on wells up to 200 feet. Slightly less expensive at $800-1,500. Well-reviewed and durable. A solid alternative to the Simple Pump.

Both require professional installation — you're dropping a pump cylinder and pipe string down your well casing. It's not a weekend DIY project. Budget $300-500 for installation on top of the pump cost.

The output is modest: about 5 gallons per minute of pumping on shallow wells, less as depth increases. At 150 feet, you're working hard for every gallon. But it's water, and it works when nothing else does.

limitations

• Only practical for wells under 200 feet (Simple Pump stretches to 325 feet, but it's a serious workout)
• Not all well casings can accommodate both a submersible pump and a hand pump — check your casing diameter
• Flow rate is low — you're filling buckets, not running a household at full pressure
• Requires physical effort, which matters if elderly or disabled household members need water access

option 3: stored water

This is the simplest, cheapest, and most universally applicable solution. Store water before you need it. No equipment to buy (beyond containers), no installation, no fuel, no moving parts.

The standard guideline is 1 gallon per person per day, and that's a minimum. One gallon covers drinking and basic sanitation. It does not cover cooking, cleaning, flushing toilets, or keeping a household running normally. For that, you want closer to 2-3 gallons per person per day.

For a family of four planning for a three-day outage:

• Minimum: 12 gallons (4 people x 3 days x 1 gallon)
• Comfortable: 24-36 gallons (4 people x 3 days x 2-3 gallons)

Storage options:

• 5-gallon food-grade jugs. Stackable, easy to handle, pourable with a spout. Three to six of these covers most families. About $15 each.
• 55-gallon water barrel. More storage in less floor space. Requires a pump or spigot to dispense. About $60-90. Keep it in the basement or garage.
• Commercially bottled water. Cases of gallon jugs from the grocery store. No rotation needed until the expiration date, which is usually 2+ years out. Easy and cheap, but takes up more space than dedicated containers.

Rotate stored water every 6-12 months if you're using your own containers. Water itself doesn't expire, but containers can leach chemicals or grow algae if stored in sunlight or heat. Keep stored water in a cool, dark place.

For more on water in your outage supplies, see the water section of the power outage kit guide.

option 4: gravity-fed tank system

This is the premium solution. Install an elevated storage tank (or a tank on a hill if your property has one) and fill it from your well when you have power. When the power goes out, gravity pushes water through your pipes without any electricity at all.

A 500-gallon elevated tank gives a family of four roughly a week of conservative water use. A 1,000-gallon tank extends that to two weeks. The water pressure won't match what your pressure tank provides — gravity gives you about 0.43 PSI per foot of elevation — but it's enough for faucets and toilets.

This is more common in rural and off-grid setups. The tank costs $500-2,000 depending on size and material. The tower or elevated platform adds another $1,000-3,000. Plumbing to tie it into your system adds more. Total installed cost: $2,000-6,000.

It's not for everyone. But if you live somewhere with frequent extended outages and you want water that just works without fuel or effort, a gravity-fed tank is the most resilient option available.

preparing ahead: what to do before the outage

Everything above works better — or only works at all — if you prepare before the power goes out. Here's the checklist.

know your pump

• Horsepower. Check the label on your well pump control box or pressure switch. Common residential sizes: 1/2 HP, 3/4 HP, 1 HP, 1.5 HP.
• Voltage. Most pumps are 240V. Some smaller pumps are 120V. This matters for generator selection and wiring.
• Well depth. Your well driller's report should list this. If you don't have it, your county health department or well permitting office usually has records. Depth determines whether a hand pump is viable.
• Pressure tank size. Read the label on the tank. Know how much usable water you have when the power drops.

size your generator correctly

The single most common mistake: buying a generator that can handle the pump's running watts but not the startup surge. Your well pump draws 2-4 times its running wattage for the first 2-3 seconds when it kicks on. If your generator can't deliver that surge, the pump won't start.

For the full sizing breakdown, see best generator for well pump.

store water now

• Minimum 1 gallon per person per day for 3 days
• More is better — 2-3 gallons per person per day if you have space
• Don't forget pets. A medium dog needs about 1/2 gallon per day.
• Rotate every 6-12 months
• Store in a cool, dark place in food-grade containers

get a transfer switch installed

If you have a generator (or plan to buy one), get a transfer switch installed before you need it. During an outage is not the time to figure out how to safely connect a generator to your well pump circuit. An electrician can install a transfer switch in a few hours. Cost: $300-800. Call before storm season.

battery backup options for well pumps

Battery backup systems are improving fast, and they're now viable for well pump backup in certain situations. The challenge is that well pumps are power-hungry and their startup surge demands a beefy inverter.

What you need in a battery backup for a well pump:

• Pure sine wave inverter. Well pumps are inductive motors. They don't play well with modified sine wave inverters. Pure sine wave only.
• Sufficient surge rating. The inverter needs to handle your pump's startup surge — typically 2-4x the running watts. A 1/2 HP pump needs an inverter that can surge to at least 3,000 watts.
• Enough capacity. Running a 1,000-watt pump for 20 minutes uses about 330 watt-hours. If you need to run the pump 3-4 times per day, that's about 1,000-1,300 Wh per day just for water.

Systems that can handle it:

• EcoFlow Delta Pro (3,600Wh, 4,500W surge). Can run most 1/2 HP well pumps for 4-6 fill cycles. Rechargeable via solar panels. About $2,500-3,500.
• Bluetti AC200MAX (2,048Wh, expandable). Handles smaller pumps. Add expansion batteries for more cycles. About $1,800-2,200.
• Whole-home battery systems (Tesla Powerwall, Enphase, etc.). These are permanent installations with 10-13 kWh of capacity — enough to run a well pump for days. But they cost $10,000-15,000 installed and require professional installation.

Battery backup makes the most sense if your outages are short (under 24 hours), you have solar panels for recharging, or you want silent backup without fuel storage. For multi-day outages, a generator is still more practical and far cheaper per watt-hour.

water purification if using alternative sources

If your stored water runs out and your pump isn't running, you may need to use water from streams, ponds, rain barrels, or other non-treated sources. This water is not safe to drink without treatment. Period.

Three options for field purification:

• Boiling. A rolling boil for 1 minute (3 minutes above 6,500 feet elevation) kills bacteria, viruses, and parasites. Requires a heat source — camp stove, fire, or a way to heat water electrically. The simplest and most reliable method.
• Portable filter. The Sawyer Squeeze or LifeStraw remove 99.99% of bacteria and protozoa. They do not remove viruses — for U.S. surface water, this is usually acceptable. About $25-35 and good for thousands of gallons.
• Chemical treatment. Unscented household bleach (8.25% sodium hypochlorite): 2 drops per quart of clear water, wait 30 minutes. Or use commercial purification tablets like Potable Aqua. About $10 for 50 tablets.

If you're pulling water from an unknown source, filter first to remove sediment and particulates, then chemically treat or boil as a second step. Belt and suspenders.

putting it all together

If I were starting from zero on well water today, here's the order I'd prioritize:

1. Store water. Right now, today. Buy four 5-gallon jugs and fill them. Cost: $60. Time: 20 minutes. This alone covers your family for 3-5 days of drinking water.
2. Know your pump specs. Walk to your pressure tank right now and read the labels. Write down the HP, voltage, and tank size. Stick that note on the inside of your electrical panel door.
3. Buy a properly sized generator. See the table above. Get one that handles the startup surge with margin. A good portable generator for well pump duty costs $400-800.
4. Get a transfer switch installed. Call an electrician. $300-800. Do this before storm season.
5. Consider a hand pump if your well is under 200 feet. $800-2,000 plus installation. This is your backup to the backup.
6. Consider a battery backup if you want silent, fume-free backup and your outages are typically short. $1,800-3,500 for a portable system.

Steps 1 and 2 cost under $60 total and take less than an hour. Steps 3 and 4 cost under $1,500 total and solve the problem for virtually any outage. Steps 5 and 6 are insurance for worst-case scenarios.

For the broader picture on outage preparedness, start with what to do when the power goes out and the power outage kit guide. Browse all preparedness content at guides.