Sump Pump, Prostormer 1HP 3700GPH Submersible Clean/Dirty Wa

The Verdict

When the forecast calls for relentless rain, the last thing you want is a $200 pump that handles a trickle but chokes on a surge. The Prostormer 1HP 3700GPH submersible pump is built for the homeowner who’s been burned before. It’s not the cheapest option, and it’s not the quietest, but it moves water with an authority that cheaper plastic pumps just don’t have.

What’s Actually in the Box

You get the pump itself—a hefty unit that’s visibly cast iron on top, not thin stamped metal—plus a 10-foot power cord, a 2-inch and 1.5-inch NPT threaded adapter, and a manual. There’s no float switch to assemble; the tethered float arrives pre-wired and mounted. The pump measures roughly 11 inches tall and 9 inches wide, so it fits most standard 18-inch sump basins without scraping the sides. The intake screen sits low, which matters because it pulls water down to about 1/8 inch of residual, minimizing that annoying “slurping” sound at the end of a cycle.

Real-World Performance: The Numbers That Matter

This is a 1HP motor pushing 3700 gallons per hour at a 10-foot head. That’s not marketing math—that’s the spec at a realistic lift height for a basement discharge line. If you’re pumping straight out a ground-level window, you’ll see closer to the theoretical max of 4600 GPH. The stainless steel impeller handles solids up to 1/2 inch, which means it won’t jam on the gravel, sand, or small debris that inevitably finds its way into a sump pit. One reviewer noted, “Pumped out a flooded crawlspace in under 20 minutes where my old pump took two hours,” and that tracks with the flow curve.

What Buyers Keep Praising

The dominant theme in the 210 ratings is reliability under pressure. A verified buyer wrote: “This thing is a beast. My sump pit filled every 90 seconds during a downpour, and it never skipped a beat. The cast iron top doesn’t flex like the plastic ones.” Another specifically called out the thermal overload protection: “Ran it for two hours straight in a construction site trench. It got warm but never shut off.” The dual discharge ports also get consistent love—you can plumb it vertically or horizontally without buying extra adapters, which saves a trip to the hardware store.

Where It Falls Short

Be honest with yourself about your electrical setup. This pump draws 3 amps at 115V, but startup surge can spike higher. If your sump pump outlet shares a circuit with a freezer or a microwave, you’re risking a tripped breaker at the worst possible moment. Plan for a dedicated circuit.

The tethered float switch is also a double-edged sword. It’s reliable, but it needs room to swing. In a shallow basin—anything under 10 inches deep—the float won’t drop far enough to trigger the pump, leaving you with a full pit and a dry pump. If your sump hole is shallow, look for a vertical float model instead.

And the elephant in the room: no battery backup. This is a grid-dependent pump. If a storm knocks out your power, the pump sits idle while your basement floods. For that, you’d need a separate backup system or a pump with an integrated battery—which this isn’t.

Who Should Buy This

• The homeowner with a history of wet basements: If your existing pump died mid-storm, this is a direct, powerful replacement.
• The property manager with a crawlspace or low-lying area: The debris handling and 3700 GPH flow make it suitable for dirty water transfer, not just sump duty.
• The DIYer who wants a fixed installation: The dual ports and standard NPT threading make it straightforward to plumb without custom parts.

Skip it if you need a backup pump with battery power, if your sump basin is unusually shallow, or if you only need to handle seepage at 1000 GPH—that’s overkill and you’ll pay for unused capacity.

FAQ: Three Questions Shoppers Actually Ask

Can this handle sandy or muddy water? Yes, up to 1/2-inch solids. The stainless steel impeller and wear-resistant design handle sediment without seizing, but don’t run it dry—that will damage the seals.

Does it come with a check valve? No. You’ll need to buy a separate check valve for the discharge line to prevent backflow and short-cycling. Factor that into your budget.

How loud is it? It’s noticeably louder than a 1/3HP model—a low hum that’s audible through the floor. Not deafening, but you’ll hear it running. Insulating the basin lid helps.

The Verdict

Rating: 4.2/5

The Prostormer 1HP 3700GPH delivers exactly what it promises: aggressive water removal, durable construction, and no-nonsense operation. The cast iron housing and stainless impeller give it a lifespan that cheap plastic pumps won’t match, and the flow rate is genuinely impressive for the price point. The lack of battery backup and the float switch’s minimum depth requirement are real limitations, but they don’t disqualify it for its primary purpose.

Buy it if you need reliable, high-volume pumping for a standard basement sump pit and you have a dedicated circuit available.

Skip it if you’re in a flood-prone area with frequent power outages, or if your basin is too shallow for a tethered float.

Where to Buy

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.