Pump horsepower from GPM and head height, basin, check valve, discharge pipe and a dedicated circuit.
Estimates are planning aids, not a professional quote. Double-check quantities and product coverage — and any local code or permit requirements — before you buy.
⚠ A power outage during a heavy storm is exactly when a sump pump is needed most, and this plan has no backup: no battery-backup pump and no high-water alarm. At minimum, add the alarm so you find out before the basement floods.
| Drainage | $273–$369 |
| Total | $273–$369 |
Excludes tools, delivery, tax and permit fees. Labor not included — this is a DIY materials estimate.
These are affiliate links: we may earn a commission if you buy through them, at no extra cost to you. It never changes what the calculator recommends — the shopping list comes from your dimensions, not from what pays.
About this calculator
The Sump Pump Builder sizes the pump itself, not just the parts list — enter how much water the pit needs to move and how high and how far the discharge line has to travel, and it works out the total dynamic head, picks the smallest horsepower class that clears it, and lists the basin, check valve, discharge pipe and fittings that go with it.
Open advanced options to set pipe diameter and elbow count, since both feed the friction-loss side of the head calculation, plus a battery backup for storm outages, a dedicated GFCI circuit, and a high-water alarm. This covers a new sump pit and pump, not a like-for-like pump swap into an existing basin — if you're only replacing a failed pump, most of the basin and pipe lines below won't apply to you.
Step by step
A step-by-step walkthrough to go with your plan above. Follow the product instructions and any local code or permit requirements as you work.
Find the lowest point where water collects and use your inflow rate, lift and discharge run to size the pump — undersizing on total dynamic head, not flow alone, is the most common mistake.
Break out the slab opening with a rotary hammer, dig the pit to the basin's depth plus a couple inches, and bed the bottom with pea gravel so it drains and sits level.
Drop the basin into the excavation, check it sits flush and level with the surrounding floor, and backfill and patch the slab around the rim.
Install the check valve just above the pump, then run rigid PVC up and out through the rim joist or foundation wall, gluing every joint and keeping the exit point clear of ice-prone areas.
Run a dedicated 20A GFCI-protected circuit to a nearby outlet — hire an electrician for the panel work if you're not confident opening it yourself.
Install a battery-backup pump in the same basin, or at minimum a high-water alarm, so the pit has some protection the one time it's needed during a power outage.
Fit the basin's sealed lid with a grommet for the discharge pipe and power cord — a sealed cover cuts down on basement humidity and radon intrusion, not just noise.
Pour water into the pit until the pump activates, confirm it shuts off cleanly without short-cycling, and check the discharge point outside to make sure water is actually clearing the foundation.
Equip the job
Hand-picked categories that match the shopping list above. Links open a current selection so you can compare brands and prices.
These are affiliate links: we may earn a commission if you buy through them, at no extra cost to you. It never changes what the calculator recommends — the shopping list comes from your dimensions, not from what pays.
As an Amazon Associate I earn from qualifying purchases. We may also earn from other retailer links here. This doesn’t change your price and helps keep these planners free.
Keep planning
Concrete & Masonry
Answers
Pump size isn't just about how much water your pit takes on — it's flow (GPM) against total dynamic head, the vertical lift to the discharge point plus friction loss from the horizontal run and every elbow. A pump rated for 46 GPM at zero head might only move half that once it's lifting 10 feet and pushing through 30 feet of pipe with a few bends. This calculator sizes from both numbers together and picks the smallest horsepower class that still clears your actual head, which is the number that matters, not the pump's headline flow rating.
If your basement floods during the same storms that knock out power, a primary pump alone won't help you when it matters most. A battery-backup unit sits in the same basin and kicks in automatically if the primary pump loses power or fails, buying hours of runtime on a fully charged battery. It's not required everywhere, but it's the single upgrade most worth the extra cost if flooding risk is real and outages are common in your area.
A sump pump draws a real electrical load and needs to run uninterrupted exactly when storms are stressing the rest of the house's circuits. Most electrical codes require it on its own GFCI-protected circuit rather than sharing an outlet with a freezer, dehumidifier or shop tools, where a tripped breaker on someone else's equipment can silently take the pump down too. If you're not comfortable opening a breaker panel, this is the one part of the job worth hiring out even on an otherwise DIY install.
Without it, all the water sitting in the discharge pipe above the pump drains straight back down into the pit the instant the pump shuts off, so the pump immediately has to lift that same water again on the next cycle. That constant short-cycling is one of the most common reasons pumps burn out well before their rated lifespan. A swing check valve installed just above the pump keeps that column of water up in the pipe between cycles, so the pump only ever moves new water.
Out and genuinely away from the foundation — a few feet isn't enough, because that water just seeps back down and refills the same pit it came from. Daylighting to a lower point on the property, tying into a dry well, or routing to an approved drainage easement all work, as long as the discharge point is clearly lower than and pointed away from the foundation. In freeze-prone climates, keep the outlet clear of ice buildup every winter, since a frozen discharge line backs the pump up against a closed pipe.
This calculator sizes a complete new install — pit, basin, pump, discharge line and the electrical to run it. If you're swapping a failed pump into a basin that's already in place, most of the basin, pipe and fitting quantities here won't apply; you'd really only need the pump line itself sized to your existing head and flow. For a swap, measure the actual rise from the pit to where the pipe leaves the house rather than reusing the old pump's nameplate rating — the failed unit may well have been undersized for that head all along, which is often why it wore out early. It's also worth replacing the check valve at the same time, since it's cheap and already in the way.