Best Sump Pumps for Basements and Well Pits (Driller Picks)
A sump pump is cheap insurance until the day it fails in a storm. I install them in basements, well pits and pump houses, where a flooded pit can ruin a pressure tank and every wire around it.
This guide covers how to size a sump pump properly, the pumps I trust, and the installation details that decide whether it lasts three years or ten.
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| Need | Pick | |
|---|---|---|
| Best overall for most basements | Zoeller M53 Mighty-Mate (1/3 HP) | Check price |
| Best for heavy inflow | Wayne CDU980E (3/4 HP) | Check price |
| Best value cast iron | Liberty Pumps 257 (1/3 HP) | Check price |
| Best battery backup | Wayne ESP25 | Check price |
| Best for draining tanks and pits | Superior Pump 91250 utility pump | Check price |
How a Sump Pump System Works
Water collects in a pit below the floor. When it rises, a float switch starts the pump, which pushes the water up a discharge pipe and away from the house.
Two parts matter as much as the pump itself. The check valve stops water falling back into the pit, and the discharge line must end well away from the foundation or the same water returns.
How to Size a Sump Pump
Sizing comes down to two numbers: how fast water enters the pit, and how high the pump must lift it. Most people skip the first one and buy the biggest pump, which short cycles and wears out early.
Step 1: Measure your inflow
During heavy rain, mark the water level in the pit, wait one minute and measure how many inches it rose. Multiply by the gallons per inch for your pit size to get gallons per minute.
Step 2: Work out the total head
Measure the vertical lift from the pit floor to where the pipe leaves the house. Add roughly 1 foot for every 10 feet of horizontal pipe, and that is your total head.
Step 3: Match the horsepower
| Horsepower | Typical use | Lift it handles well |
|---|---|---|
| 1/4 HP | Light seepage, utility draining | Up to about 8 ft |
| 1/3 HP | Most basements and well pits | Up to about 10 ft |
| 1/2 HP | Fast filling pits, high water tables | Up to about 15 ft |
| 3/4 HP | Heavy inflow, long or high discharge | Over 15 ft |
Choose a pump that moves at least one and a half times your measured inflow at your total head. Check the maker’s pump curve, because the flow at 10 feet is far lower than the headline number at 0 feet.
The Best Sump Pumps
Zoeller M53 Mighty-Mate
The M53 has a long track record of running for years in service. It has a cast iron body, a reliable float switch and a 1/3 HP motor that suits the typical basement or well pit.
- Power: 1/3 HP
- Build: cast iron housing
- Switch: automatic float
Proven durability, quiet, widely stocked parts.
Not enough for very heavy inflow.
Wayne CDU980E
When a pit fills fast or the water must travel far, the CDU980E has the extra muscle. Its 3/4 HP motor, cast iron and stainless build and vertical float suit high water tables and long discharge runs.
- Power: 3/4 HP
- Build: cast iron and stainless steel
- Switch: vertical float
High capacity, handles tough sites.
Oversized for a small pit with light seepage.
Liberty Pumps 257
The Liberty 257 gives you a cast iron 1/3 HP pump at a friendly price. It is a dependable choice for a standard pit when you want durability without paying for capacity you do not need.
- Power: 1/3 HP
- Build: cast iron
- Switch: vertical float
Solid build for the money.
Fewer features than premium models.
Wayne ESP25 Battery Backup
Storms knock out power exactly when your pit fills. The ESP25 sits beside your main pump and runs from a 12 volt battery, with an alarm so you know when it takes over.
- Runs on: 12 volt battery, sold separately
- Fits: beside your main pump
- Alerts: audible alarm
Protects the basement through power cuts.
Battery needs checking and replacing.
Superior Pump 91250
For draining a storage tank, a flooded well pit or a water heater, a portable utility pump is the right tool. The 91250 connects to a garden hose and runs by hand, so it does not need a pit or float.
- Power: 1/4 HP
- Connection: garden hose thread
- Use: manual draining jobs
Light, cheap and handy around any well site.
Not for permanent sump duty.
Submersible vs Pedestal Sump Pumps
Submersible pumps sit underwater in the pit, while pedestal pumps keep the motor on a column above it. For almost every home I fit a submersible pump, and the table shows why.
| Submersible | Pedestal | |
|---|---|---|
| Noise | Quiet, water muffles it | Louder, motor in the open |
| Pit size | Needs a pit 18 inches or wider | Fits narrow pits |
| Motor cooling | Cooled by the water | Air cooled |
| Lifespan | Typically 7 to 10 years for cast iron | Often longer, easy to service |
| Best for | Basements, well pits, pump houses | Shallow or narrow pits |
Sump Pumps for Well Pits and Pump Houses
Older wells often sit in a pit below ground, and many rural homes have the pressure tank in a small pump house. Both flood easily, and a flooded pit can short the pressure switch, rust the tank and contaminate the well through a loose cap.
A 1/3 HP submersible with a vertical float is usually enough for a well pit. Route the discharge downhill and well away from the wellhead, and seal the well cap so surface water cannot get in. My guide to sanitary well caps covers the seal.
Common Sump Pump Problems and Fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Pump runs but no water moves | Air lock or clogged intake | Drill a weep hole, clean the screen |
| Pump cycles every few seconds | Float set too short or no check valve | Adjust the float, add a check valve |
| Pump never shuts off | Float stuck or switch failed | Free the float or replace the switch |
| Pump hums but will not start | Jammed impeller or failing motor | Clear debris, replace if it persists |
| Basement still floods | Pump too small or power cut | Size by inflow, add a battery backup |
A Common Case: A Flooded Pump House
A pump house below a slope can flood in every storm, soaking the pressure switch and tripping the pump. A small sump pit in the corner with a 1/3 HP submersible, a check valve and a discharge run well downhill keeps the floor dry. Lifting the pressure tank and switch onto blocks adds a second layer of protection.
Installation Tips
- Set the pump on a solid base such as a paver or brick, so it does not suck up silt from the pit floor.
- Drill a 1/8 inch weep hole in the discharge pipe just above the pump and below the check valve to prevent air lock.
- Fit a check valve and support the discharge pipe so the valve does not bang when it closes.
- Give the float room to move so it cannot snag on the pit wall or the power cord.
- Use a dedicated GFCI outlet where your local code requires it, and never run the pump on an extension cord.
- Test it every season by filling the pit with a bucket of water and watching a full cycle.
If your pit is in a pump house, read my guides to keeping a well pump from freezing and float switches for tanks. For power cuts, see the best generators for well pump backup.
Frequently Asked Questions
What size sump pump do I need?
Most homes do well with a 1/3 HP pump. Choose 1/2 HP if your pit fills fast in storms or the water must lift more than about 10 feet, and 3/4 HP for very high water tables.
How long does a sump pump last?
A good cast iron pump often lasts 7 to 10 years, and cheaper plastic pumps less. Heavy cycling, debris and running dry shorten that.
Should a sump pump have a check valve?
Yes. A check valve stops the water in the discharge pipe falling back into the pit, which saves the pump from restarting on the same water.
Can I use a sump pump to drain a well pit or pump house?
Yes. A sump pump with a float switch keeps well pits and pump houses dry, which protects the wellhead, pressure tank and wiring from flooding.
Do I need a battery backup sump pump?
If your basement has ever flooded, or storms often cut your power, a battery backup is worth it. Power cuts and heavy rain usually arrive together.
