What are the best water-powered sump pumps?

A water-powered sump pump runs on your home’s municipal water pressure instead of electricity, so it can keep pumping when the power is out and your main pump quits. The catch is that it only works on town water with strong pressure, and it wastes a lot of water while it runs. For most New Hampshire basements we waterproof, we install a battery backup instead, because a charged backup battery can move about a residential pool’s worth of water, roughly 15,000 to 20,000 gallons, on one charge.

A water-powered pump has no motor and no battery. It uses the pressure from your city water line to create suction and pull water out of the pit, no electricity needed. That sounds great until you look at the trade-offs.

First, it needs town water. On a private well, the well pump runs on electricity too, so a power outage takes out your backup along with your main pump. That rules out a big share of homes up here in NH and Maine. Second, it needs strong, steady pressure, and weak pumping during a real storm is not much of a backup. Third, it drinks water. For every gallon it pumps out, it sends a good amount of city water down the drain, and over a long outage that shows up on your bill.

So what makes a good one? If you are set on water-powered, you want a unit rated for your pressure and incoming pipe size, with a backflow preventer so basement water can never get back into your drinking supply, plus a clear pumping rate at your actual pressure. We will not name a brand here, because the right pick depends on your plumbing and the model lineup keeps changing [verify].

Most folks asking this want one thing: the pump to work when the lights go out. A battery backup does that without touching your water line. That is why it is the backup we standard on with the Forever Dry System, our full basement waterproofing setup: full-perimeter interior drainage, a primary sump pump sized at 1/2 hp per 120 feet of drain, a 12-mil wall vapor barrier, and a dehumidifier. The sump pump system carries a 3-year warranty (batteries are excluded), and the whole system is 100% guaranteed to be dry for life!

You may not need a fancy backup yet. If your basement only seeps in heavy spring melt and your main pump is healthy, a single quality pump on a working circuit gets a lot of folks through the year. We will tell you that during the inspection, because we would rather right-size it than oversell you.

Why is water coming in at all? When your house was built, the crew dug a hole, set the foundation, then shoved the dirt back. That backfill is looser than the packed ground around it, so it drains slow, holds water, and pools against your foundation. Add NH frost heave pushing walls inward over winters, and the pit fills. A pump is the last line of defense. The real fix is interior drainage that catches water at the floor wall joint and carries it to the pit before it reaches your floor. The U.S. Department of Energy’s Building America program notes that managing below-grade water is central to a dry, durable basement (basc.pnnl.gov) [verify].

One thing we do not do is dig up your yard to “waterproof” the outside. In our field experience that exterior excavation fix tends to fail in about two to three years, and then you are back to square one with a torn-up lawn. Interior drainage lasts.

Basement waterproofing with the Forever Dry System runs $3,000 to $30,000. What drives the number is how many feet of drain you need, the pump and backup you choose, and access. We give you a free inspection, a free estimate, and a written quote within 24 hours. Financing is available through Hearth, subject to approval (we make nothing on it).

If your wet space is a crawl space, the fix is crawlspace encapsulation, not Forever Dry, and that runs $3,000 to $25,000. Different problem, different system. See /crawl-space-services/.

Trusted by 5,000+ homeowners across New England, rated 4.9 on Google across 250 reviews, BBB A+ accredited, licensed and insured. We self-perform the work with our own crew.

Ready to figure out the right backup for your basement? Call us at 603-610-1770 or book your free inspection. We will look at your pit, pump, and water, then tell you what you need.

Learn more: basement waterproofing and the 603 guarantee.

Related questions

Is a water-powered or battery backup sump pump better? For most homes we serve, a battery backup. It works on well water or town water, it does not waste water, and a charged backup battery moves about 15,000 to 20,000 gallons, roughly a residential pool, on one charge. Water-powered only makes sense on strong-pressure town water. Our backup is battery only.

Do water-powered sump pumps work during a power outage? Yes, that is the point of them, since they run on water pressure, not electricity. But if you are on a well, your well pump needs power too, so the backup dies with the outage. On town water with good pressure, they will keep pumping.

How long does a battery backup sump pump last in an outage? On a full charge, it can pump about a pool’s worth of water, roughly 15,000 to 20,000 gallons, before it needs power back. Actual run time depends on how fast water is coming in. The sump pump system carries a 3-year warranty; batteries are excluded.

What if water is coming in even with a working pump? The pump is only catching what reaches the pit. If water still shows on the floor, you likely need full-perimeter interior drainage at the floor wall joint. That is the Forever Dry System, and it is what stops the water for good. Book a free inspection.