How do I keep my sump pump running during a power outage?

Key facts

• A battery backup sump pump runs on battery power during a power outage.
• Motor-driven appliances can need up to three times their normal wattage to start, so size the generator for the start-up load.
• If the generator is too small, take turns running the sump pump, furnace and freezer until power returns.
• A generator connected the wrong way can feed power back into the power lines.
• Without a transfer switch, plug the pump directly into the generator.
• Run generators outdoors, at least 20 feet from windows, doors and attached garages.
• Put carbon monoxide detectors with battery backup on every level of your home.

Ways to keep a sump pump running in an outage

What keeps a sump pump running when the power goes out?

A battery backup sump pump or a portable generator keeps water moving out of the pit when the power fails. Your main sump pump runs on house power. When the power stops, the main pump stops too, and the pit keeps filling.

A battery backup system has its own pump and a battery. It runs the backup pump during the outage, with no action from you. This matters when the power goes out at night or while you are away.

A portable generator needs a person at home to start it and connect the pump. It can run the pump for as long as you have fuel. It also brings carbon monoxide and shock risks, so it needs a safe setup.

Many homes use both. The battery backup covers the first hours, and the generator takes over in a long outage.

How does a battery backup sump pump work?

A battery backup sump pump uses a battery to run a second pump when house power stops. It sits in the same pit as the main pump. The backup also starts if the main pump float sticks or fails and the water keeps rising.

Many systems sound an alarm when the battery, the pump or the power needs attention. Do not ignore that alarm. A backup with a dead battery does nothing in a storm.

A battery wears out with age. If the battery runs low on water often, the maker of one system says it may be time to replace it. A local auto service station can load-test the battery.

1. Read the manual for your backup system and keep it near the pit.
2. Check that the battery charger is plugged in and the control box shows no warning.
3. Check the water level in a wet-cell battery on the schedule in the manual.
4. Have the battery load-tested if it is old or the alarm warns about it.
5. Pour water into the pit to make sure the pumps start and the water drains out.

Can I run my sump pump on a portable generator?

Yes, a portable generator can run a sump pump if the generator is big enough and you set it up safely. First, add up the wattage of everything you want to run during the outage. That total is your constant wattage.

A sump pump has a motor. Motors need extra power for a moment when they start. The generator needs a surge rating that covers that start-up load.

If the generator cannot run everything at once, share the power. Unplug some items and plug in others. You can run the sump pump, then the furnace, then the freezer, in turns, until the power comes back.

1. Find the wattage on the sump pump label or in its manual.
2. Add the wattage of the other items you need, such as the furnace blower and the refrigerator.
3. Pick a generator with a running rating above your total and a surge rating that covers start-up loads.
4. Turn off all appliances before you start the generator, then turn them on item by item.
5. Use only heavy, grounded extension cords sized for the load.

How do I connect a generator to my house safely?

Use a transfer switch put in by a qualified electrician, or plug the pump straight into the generator. Never plug a generator into a wall outlet. A generator connected the wrong way can send power back into the power lines. This is backfeed, and it can hurt or kill line crews and neighbors.

If you do not have a transfer switch, plug the sump pump directly into the generator with a proper extension cord. For extra safety, switch your main breakers to off.

Run the generator outside only. Keep it at least 20 feet from windows, doors and attached garages. Never run it in the basement, the garage or a shed. Keep it dry, and turn it off before you add fuel.

Put carbon monoxide detectors with battery backup on every level of your home. A permit may be needed to install a generator, so ask your city building department.

1. Ask an electrician if a transfer switch fits your panel and what it will power.
2. Ask who pulls the permit and who books the inspection.
3. Mark a dry, outdoor spot for the generator, away from doors and windows.
4. Test the setup on a clear day, before the next storm.

What should I do if my basement floods during an outage?

Stay safe first, then document the damage before you clean up. Do not walk into standing water if outlets, cords or appliances are wet. Wait until the power to the basement is off.

Take photos and video of the water line, the sump pit and every damaged item. Write down when the power went out and when you found the water. Keep receipts for anything you buy to stop more damage, such as fans or a pump rental.

Whether your policy pays for this damage depends on the policy wording and the endorsements on it. Look at your declarations page for words such as water backup, sump overflow or sump pump failure, and the limit next to them.

Before you make any calls, have the damage documented. A local restoration pro does this free. Wet drywall, carpet and framing can grow mold, so drying starts as soon as it is safe.

Sources, quoted

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