The power flickers, dies, and about thirty seconds later your shower goes from hot to nothing. That’s not bad luck. That’s exactly how a well pump works, and it’s why a real power outage well water backup plan needs more than a flashlight and a case of bottled water. No electricity means no pump, and no pump means no water, no matter how deep or productive your well is.
Homes on city water barely notice most outages. Homes on a private well anywhere from Wenatchee to Quincy lose water the instant the grid does. A solid backup plan comes down to three layers: knowing how much water your pressure tank actually has in reserve, keeping enough stored water on hand for outages that run long, and deciding whether a generator or battery backup fits your pump.
If you’re not sure which layer your household is missing, talk to us about a free assessment or call (509) 300-5151 and we’ll walk through your setup instead of guessing.
Why a Power Outage Kills Your Well Water Before Anything Else Does
Every well pump on a private system, submersible or jet, runs on electricity from your panel. There’s no battery inside the pump itself and no gravity feed from a water tower like a city system has. When the grid goes down, the pump stops turning, period.
That catches people off guard because the well itself doesn’t run dry. The water is still down there, sometimes hundreds of feet below ground out toward Leavenworth and Plain, waiting without power to move it. The problem isn’t supply. Nothing in a standard well system can lift that water without electricity.
Your pressure tank buys you a short grace period, and we’ll get to exactly how short in a minute. After that, the tap runs dry until either the power comes back or something else does the pump’s job. That’s the entire logic behind a power outage well water backup plan: buy time with the tank, extend it with stored water, and cover longer outages with generator or battery power.
Pressure Tank Drawdown: How Long Your Well Water Lasts During a Power Outage
Most homeowners assume their pressure tank holds more water than it does. A pressure tank isn’t a reservoir. It’s a small buffer of water sitting on a cushion of compressed air, and only the water between your pump’s cut-in and cut-out pressure is actually usable. That usable slice is called drawdown, and it’s almost always a fraction of the tank’s total size.
A standard 20-gallon pressure tank has maybe 5 to 6 gallons of real drawdown. A larger 44-gallon tank might give you 12 to 14 gallons. Run a shower at 2.5 gallons a minute, flush a toilet, and start a load of laundry, and a 20-gallon tank’s drawdown can vanish in under five minutes once the power’s out.
Curtis, who farms a few acres outside Moses Lake, found this out during a windstorm outage last winter. His family kept the taps running like normal, two showers and a dishwasher load, assuming the tank would carry them until power came back. Water quit in under ten minutes. He called us afterward, and we upgraded him to a larger 44-gallon tank for $1,050 along with 30 gallons of stored water in food-grade containers.
Knowing your tank’s drawdown changes how you use water during an outage. Once the power’s out, treat every gallon like it’s the last one until you know your generator or stored water is covering you. Skip laundry and long showers, and check that your pressure tank isn’t already waterlogged and shortchanging you before an outage ever hits.
How Much Stored Water You Need for a Well Water Power Outage
The Washington State Department of Health recommends storing at least one gallon of drinking water per person per day, with a minimum three-day supply for any household (doh.wa.gov). On a well, we’d push that further. A three-day supply covers drinking and basic hygiene, not flushing toilets or running a dishwasher, so plan on more if you want any normalcy.
A family of four covers the DOH minimum with just 12 gallons, but that’s bare survival math. We tell customers to keep 20 to 30 gallons on hand in food-grade containers, rotated every six months, plus extra per pet or head of livestock. Setting that up runs $50 to $150, one of the cheapest parts of any power outage well water backup plan.
The Osei family, who live outside Leavenworth, went through an outage in 2025 that stretched almost 30 hours after a wildfire took out a nearby transmission line. They had no stored water and no generator. For two days they drove twenty minutes each way to shower at a relative’s house in Cashmere and hauled drinking water back in jugs. Afterward they spent about $180 on stackable water containers and a simple rotation system, cheap insurance against the next multi-day outage.
Stored water in containers is an emergency reserve, meant to bridge you through the outage itself. That’s different from a cistern water storage system, which is a permanent fix for a well that can’t produce water fast enough even with the power on. If your well tests weak on yield rather than just losing power occasionally, our guide to cistern water storage systems covers that separate problem in detail. Some rural properties end up with both, a cistern for daily low-yield struggles and a stored water reserve for outages on top of that.
If you’re unsure whether your situation calls for stored water, a cistern, or both, reach out for a free property walk-through and we’ll tell you honestly which one applies.
Generator or Battery Backup: Powering Your Well Pump Through an Outage
Stored water and tank awareness buy you hours to a couple of days. For outages that run longer, ice storms, wildfire line damage, or a bad windstorm, something needs to actually power the pump. That’s either a generator or a battery backup system, and the right choice depends on how often you lose power and how much you want to spend.
We cover the full generator sizing math, wattage charts, and safe hookup rules in our generator for well pump guide. This section is about choosing a category, not sizing one, so if you already know you want a generator, that guide has the numbers.
A portable generator with a 240-volt outlet, paired with a transfer switch or interlock kit from a licensed electrician, is the most common setup we install across Chelan, Douglas, and Grant counties. Expect $700 to $1,500 for the generator and another $300 to $1,000 for the switch or interlock.
A battery backup system works differently. A bank of deep-cycle batteries feeds a dedicated backup pump or an inverter wired into your pump circuit through a control panel. There’s no noise, no fuel to store, and nothing to start outside in a storm. The tradeoff is runtime: typically several hours up to about a day depending on battery bank size, then it needs the grid or a generator to recharge.
Denise, who lives in East Wenatchee, wanted backup power for her half-horsepower pump but didn’t want a generator running outside her bedroom window at 2 a.m. She installed a battery backup system for $2,400 in early 2026. During a 14-hour ice storm outage that February, the system carried her pump through six or seven normal cycles without a hitch, and she says she didn’t realize the power was back until her clock radio started blinking.
Here’s how the main options stack up:
| Backup Option | Typical Installed Cost | How Long It Covers You | Best For |
|---|---|---|---|
| Stored water only | $50 - $150 | Hours to a few days, no running water | Short, infrequent outages |
| Portable generator + switch | $1,000 - $2,500 | As long as you have fuel | Occasional outages, hands-on households |
| Battery backup system | $1,800 - $3,500 | Several hours to about a day | Frequent short outages, quiet operation |
| Standby generator | $7,000 - $15,000 | Indefinite, runs on propane or natural gas | Frequent or multi-day outages, farms, livestock |
None of these options are wrong. A lot of households on a well end up running two layers together, stored water for the first hour and a generator or battery for everything after that. What matters is picking a combination that matches how often your stretch of road actually loses power, not what your neighbor bought.
Not sure which combination fits your property? Get a free backup power assessment and we’ll look at your pump size, your pressure tank, and your outage history before recommending anything.
Building Your Power Outage Well Water Backup Plan, Step by Step
Putting an actual plan together doesn’t take long. Here’s the order we walk customers through:
- Find your pressure tank’s real drawdown, so you know how many minutes you actually have.
- Store 20 to 30 gallons of water, rotated twice a year, sized up for pets, livestock, or a larger household.
- Decide between a generator and a battery backup based on how often your area loses power and for how long.
- Have a licensed electrician install a transfer switch, interlock kit, or battery control panel, never a homemade backfeed setup.
- Test the whole system twice a year, before winter storms and before the dry summer months when wildfire-related outages tend to hit our area.
Steps three and four are the parts to leave alone. Wiring a transfer switch, an interlock, or a battery backup’s control panel into your home’s electrical panel is licensed electrician work, not a weekend project. The same goes for anything at the wellhead itself, wiring splices, control box work, or pump wiring. A wrong connection can backfeed the grid and endanger a lineman working to restore power, or it can fry a pump motor that costs $1,800 to $4,500 to replace. Your safe lane is picking equipment, filling water containers, and running the test twice a year. Leave the panel and the wellhead to a pro.
Mistakes That Turn a Power Outage Into a Water Crisis
A few patterns show up after almost every outage that stretches past a few hours.
Trusting the pressure tank too long. As covered above, most tanks buy you minutes, not hours. Treat the first low-pressure sputter as your signal to switch to stored water, not a reason to keep the taps running normally.
Zero stored water on hand. It’s the cheapest layer of the whole plan and the one most often skipped. Twenty to thirty gallons in the garage costs less than a single service call.
Backfeeding the panel. Plugging a generator into a dryer outlet with a homemade double-male cord to power the whole house is illegal in Washington and can kill a utility worker restoring lines nearby. It’s also unnecessary given how affordable a proper interlock kit is.
Never testing the setup. A generator or battery system that hasn’t been started in a year is a coin flip in an actual outage. Test it on the schedule above, not the first time you actually need it.
Assuming the pump is fried if water doesn’t come back. After power returns, don’t panic if the tap stays dry. Tripped breakers and stuck pressure switches after an outage are common, and most fixes run $150 to $450 in parts and labor after a $150 to $250 service call. After-hours emergency visits add $150 to $300 on top of that, worth it at 1 a.m. in January but easy to avoid by testing your setup ahead of time. The EPA’s guidance for private well owners also recommends a look at your water quality after any extended outage or flooding event (epa.gov/privatewells). Our 24/7 emergency well service and well pump repair team in Wenatchee handle exactly these calls across Chelan, Douglas, and Grant counties.
A power outage well water backup plan isn’t about buying the biggest generator on the lot. It’s three layers working together: know your pressure tank’s real drawdown, keep enough stored water for the outages that run long, and match a generator or battery backup to how often your area actually loses power. Get those three pieces right and the next outage becomes an inconvenience instead of a crisis.
If you want an honest read on your own setup, request a free estimate or call (509) 300-5151 any time. We’ll check your tank, your pump, and your options without pushing you toward the most expensive fix.
Frequently Asked Questions
How long can I go without power before my well water runs out?
That depends entirely on your pressure tank’s drawdown, which is usually a fraction of its total size. A typical 20-gallon tank might give you 5 to 6 usable gallons, enough for a few minutes of normal use before the tap goes dry. Once that’s gone, you’re relying on stored water or a generator until the power returns or you start rationing carefully.
Do I need a whole-house generator, or will a small one work for well water?
Most well pumps only need enough generator to cover starting watts, not your whole house, so a mid-size portable unit with a 240-volt outlet often does the job. A whole-house standby generator makes more sense if outages in your area run long or frequent, or if you’re covering a well pump, a fridge, and heat all at once. Our generator for well pump guide has the full sizing chart by pump horsepower.
How much stored water should I keep for a power outage backup plan?
Washington’s Department of Health recommends at least one gallon per person per day with a three-day minimum, but that’s bare survival math for drinking and basic hygiene. We recommend most households on a well keep 20 to 30 gallons on hand in rotated, food-grade containers. Add more if you have livestock, a larger household, or outages in your area that tend to run past a day or two.
Can a battery backup run my well pump instead of a generator?
Yes, for shorter outages. A properly sized battery backup system can run a well pump through several normal cycles, typically several hours up to about a day, without any noise or fuel to manage. For outages that stretch multiple days, a generator or standby unit usually makes more practical sense since you can refuel it or let it run continuously.