DeWalt 1/3 HP Stainless Steel/Cast Iron Submersible Sump Pump

A sump pump should be the quiet adult in the room: present, reliable, and mostly invisible. After replacing the tired pedestal unit in my basement with DeWalt’s 1/3 HP sump pump, I put it through weeks of spring saturation and some intentional torture tests. The takeaway: this is a stout, well-engineered pump with strong performance and a few installation nuances worth planning for.

Installation and setup

Out of the box, the pump feels substantial. At 24 lb with a cast iron base and stainless motor housing, it sits planted in the pit and doesn’t skitter or vibrate when it kicks on. The body is compact enough for standard residential pits, but the tethered float does need room to swing; in my 18-inch basin it had no trouble, though I wouldn’t go smaller than the recommended 11–14 inches.

Plumbing is straightforward. The discharge is 2 in. FNPT, and DeWalt includes a 1-1/2 in. adapter, which is what most existing residential lines are. There’s no check valve in the box, so budget for one if you’re replacing an old valve or re-piping. I used a new 1-1/2 in. spring-loaded check valve mounted vertically about a foot above the pump to minimize water hammer.

The tethered float uses a piggy-back plug. If you’ve never wired one, it’s as simple as wall outlet > float plug > pump plug. That gives you the option to bypass the float for manual operation (handy for draining a window well or a flooded utility sink) by plugging the pump directly into the outlet. The 10 ft power cord reached my dedicated GFCI-protected receptacle without an extension—don’t use an extension cord on submersibles.

One note: this pump uses a bottom-suction design with a serviceable intake screen. Before dropping it in, I vacuumed the silt off the basin floor and set the pump on a small paver to keep the screen off any grit. The heavier base and carry handle made lowering it in easy.

Build quality and design

DeWalt leaned into durability here. The epoxy-coated cast iron volute and impeller are robust, and the stainless motor housing shrugs off the damp, corrosive world inside a pit. Internally, a thermally protected PSC motor with 100% copper windings and dual O-ring seals inspires confidence. The unit is CSA and SSPMA certified, which, in practice, has meant consistent performance under the head/flow conditions DeWalt publishes.

The bottom-suction intake and cast iron impeller are designed to handle up to 1/2 in solids. In real use, I’ve had bits of leaf debris and aggregate get drawn in without clogging. The removable intake screen is simple to clean—two screws and it’s off—so you can keep the screen clear without dismantling the pump.

Switch behavior and float clearance

Tethered floats can be polarizing, but I like them for the adjustability and longer on/off range, which helps avoid short cycling. On this pump, the switch has a comfortable swing and engages decisively. In my pit, the pump turned on at roughly mid-depth and ran long enough to evacuate the basin in one pass, which reduces starts and extends motor life.

Two tips:
- Give the float cable ample slack and a clear path. Keep it away from the discharge pipe’s joints and any pit wall irregularities.
- If you need to tweak the on height, a small adjustment of the tether on the handle makes a big difference. Don’t overdo it—too little swing can cause rapid cycling.

Performance and noise

Specs promise 75 GPM (4500 GPH) at 0 ft and 63 GPM at 10 ft, with a 25 ft shutoff head. With about 9–10 ft of vertical lift in my setup, the pump consistently cleared an ~18-gallon basin in a bit over 20 seconds. That tracks closely with the published curve and is a meaningful bump over the aging 1/3 HP unit I replaced.

Noise-wise, it’s a low, unobtrusive hum. Most of the sound in my system is the check valve’s “thunk” when the pump stops; the motor itself is quiet and free of rattles. Vibrations are minimal—again, the weight helps—and there’s no resonance through the discharge pipe that I had to tame.

The pump never broke a sweat during continuous-cycle tests. I ran it for roughly 15 back-to-back basin fills and evacuations, and the motor housing stayed warm, not hot. Thermal protection never tripped.

The anti-airlock quirk

This pump vents trapped air effectively, which is critical for bottom-suction designs. The bleed feature near the discharge does exactly what it should—prevent airlock—but it also returns a small but spirited stream of water into the pit while running. In my uncovered basin, that “mini firehose” hit the wall and produced some splash. It’s not a defect; it’s physics. But plan for it:
- A tight-fitting basin cover is your friend. It keeps splatter and humidity down and tames noise.
- Orient the pump so the bleed stream hits a solid surface low in the pit, not an elbow or open gap.
- Make this or any weep/bleed hole a quick inspection item during seasonal maintenance to ensure it isn’t clogged.

Maintenance and serviceability

Routine care is refreshingly simple:
- Quarterly: kill power, lift the pump by the handle, and rinse the intake screen. A soft brush gets silt off fast.
- Inspect the float for free movement and make sure the cable isn’t twisted or trapped.
- Verify your check valve closes cleanly and doesn’t chatter.
- Confirm the pit is free of stringy debris that could foul the impeller.

Given the materials and the motor design, I expect long service life if the pit is kept reasonably clean. The 10-year limited warranty is unusually strong for a sump pump; keep your purchase record handy and don’t treat the warranty as a substitute for a backup plan. I still use a water alarm at the pit and a secondary pump on battery in case of outages.

What could be better

No tool is perfect. Here’s what I’d flag:
- No check valve included. Many homeowners will need one; having a matched valve in the box would simplify installs.
- The bleed stream can cause backsplash in uncovered pits. Not a problem with a lid, but worth anticipating.
- The tethered float needs adequate basin diameter. If your pit is cramped or crowded with discharge piping, you may prefer a vertical switch design. This pump is rated for 11–14 in basins; I’d aim for 14 in or more for best results.
- The included adapter steps down to 1-1/2 in. piping, which is common, but you’ll realize the best flow if your system supports 2 in. discharge all the way.

Who it’s for

This 1/3 HP model is a sweet spot for typical residential drainage: moderate inflow, lift under 15 feet, and a standard 1-1/2 in. discharge. If your home sees sustained high inflow, a very deep lift, or frequent simultaneous fixtures draining into the pit, consider stepping up to a higher HP model. Otherwise, this DeWalt strikes a balance of speed, efficiency (6.5 A at 120 V), and durability that should suit most basements and crawlspaces.

It’s also a solid choice if you value:
- Quiet operation and low vibration
- Materials that resist corrosion (stainless housing, cast iron base/impeller)
- A serviceable intake and a design that tolerates small solids
- An adjustable, piggy-back float switch for manual override when needed

The bottom line

I recommend the DeWalt 1/3 HP sump pump. It’s a well-built, quiet performer that moves real water at realistic head heights, uses durable materials where it counts, and includes sensible touches like a piggy-back float and a serviceable bottom intake. You’ll need to supply your own check valve, give the tethered float room to work, and plan for a bit of bleed-back spray (ideally with a pit cover). Do those things, and you’ll have a reliable, low-drama pump that does its job without fuss—and that’s exactly what a sump pump should do.