Battery Backup for a Sump Pump in Houston: Flood Protection During Outages

The cruel math of a Houston storm is that it floods your home and cuts your power at the same time. That is exactly when a sump pump has to work hardest, and exactly when a grid-powered one quits. A home battery solves this by keeping the pump running through the outage, and the Eos controller's 17.1 kW surge starts even a large sump pump with room to spare.

Key Takeaways

• Severe storms cause flooding and power outages together, so a mains-powered sump pump fails precisely when water is rising (Ready.gov).
• Hurricane Harvey dropped 56.00 inches of rain on Friendswood, the highest total in the Houston area (NWS Houston/Galveston, 2017), and Hurricane Beryl later cut power to about 2.2 million CenterPoint customers (Houston Public Media, 2024).
• Just one inch of water can cause more than $25,000 in damage to a home (FEMA FloodSmart, 2023).
• Sump pumps draw modest running power, roughly 1,100 to 1,800 watts by size, but cycle only when pumping, so daily energy use is low.
• An Essential (9 kWh) system covers a cycling sump pump through a typical outage; step up to Plus or Pro for heavy sustained rain and to add the fridge and lights.

Can a home battery keep a sump pump running during a Houston outage?

Yes. A home battery keeps a sump pump running for the full length of an outage, which is the whole point, because the storm that floods your property is usually the same one that takes down the grid. A mains-powered pump simply stops the moment the power fails, right as groundwater and runoff peak.

Most Houston homes do not have true basements because the water table sits high, so sump pumps here protect crawlspaces, below-grade entries, French-drain systems, and flood-prone lots along the bayous. Wherever your pump sits, it only helps if it has power when the water arrives.

Why do sump pumps fail exactly when you need them?

Sump pumps fail during storms because flooding and power loss arrive together. FEMA notes that outages are most likely during severe thunderstorms, hurricanes, and winter storms (Ready.gov), which are the same events that overwhelm drainage. The pump is designed for that moment, then loses power at that moment.

Houston has lived this repeatedly. Hurricane Harvey dropped 56.00 inches of rain on Friendswood in 2017 (NWS Houston/Galveston), and Hurricane Beryl knocked out power to about 2.2 million customers in 2024 while dumping flooding rain (Houston Public Media). One inch of intrusion can cost more than $25,000 (FEMA FloodSmart), which dwarfs the cost of keeping the pump alive.

How much power does a sump pump use, and how long will a battery run it?

Sump pumps use less energy than their wattage suggests because they run in short bursts, not continuously. A common 1/3 HP pump draws around 1,115 watts, a 1/2 HP around 1,200 watts, and a 3/4 HP around 1,800 watts running, based on manufacturer amp ratings (Zoeller; Wayne). Startup draws briefly two to three times that, which the controller's surge handles easily.

Because the pump idles between cycles, even the smallest system carries it a long way. For the whole-home picture, see our

.

What size battery do you need for a sump pump?

For sump-pump protection alone, the Essential 9 kWh system covers a cycling pump through a typical outage, since the pump only pulls power when it is actually moving water. For heavy, sustained rain that runs the pump almost non-stop, or for a multi-day outage, size up so the system holds more energy.

If you want the sump pump plus your refrigerator, lights, and Wi-Fi covered, step up to the Plus 18 kWh system. In the flood-prone Houston homes we equip, most owners choose Plus so that one storm does not force a choice between dry floors and cold food.

Is a home battery better than a dedicated sump-pump backup?

Yes, for a real Houston outage. A dedicated sump-pump battery backup is a small lead-acid unit that typically lasts only a few hours before it is exhausted. That is fine for a brief blip, but Houston outages after a hurricane run for days, not hours.

A home battery runs the sump pump for the length of the outage and can power the rest of your home too, then recharges from the grid automatically once power returns. If your home sits in a flood-prone area, our

covers the local considerations in detail.

Prefer to talk it through? Call Eos at 713-207-2222 for a same-week site survey.

Frequently asked questions

Can a home battery start a sump pump?

Yes. A sump pump draws a brief startup surge of two to three times its running watts, and the Eos controller supplies 17.1 kW of surge, far more than any residential sump pump needs to start.

How long will an Essential system run my sump pump?

Through a typical outage for most homes, because the pump only draws power when it cycles on to move water. Heavy, sustained rain that runs the pump almost non-stop drains it faster, so a Plus or Pro system is the safer choice for a long storm.

Is a battery better than a dedicated sump-pump UPS?

For a Houston storm, yes. A dedicated sump-pump UPS usually lasts only a few hours, while Houston outages after a hurricane can run for days. A home battery covers the full outage and your other essentials.

Does the battery kick in automatically?

Yes. The system switches to battery power automatically the instant grid power fails, so the pump keeps cycling without anyone flipping a switch, even overnight or while you are away.

What if I also have a well pump?

You can back up both. Size up to Plus or Pro so the system runs the sump pump and the well pump together, along with your other essential circuits, through the same outage.

This article explains battery backup for sump pumps in Houston and reflects Eos specifications as of July 2026. Final sizing depends on your pump and home and is confirmed at the free site survey.