Quick Answer
To install a sump pump outside, dig a pit at the yard’s low spot about 6 to 12 inches deeper and wider than a perforated sump basin, line it with filter fabric and gravel, set the basin, and place a submersible pump with a float switch inside. Run a discharge pipe with a check valve to a storm drain, dry well or daylight outlet well away from the house, and power it from a GFCI outlet.
Key Takeaways
- An outdoor sump pit collects water at the lowest point of a yard, driveway or window well and pumps it somewhere safe.
- Use a perforated basin wrapped in filter fabric and surrounded by washed gravel so soil does not clog the pump.
- Discharge water at least 10 feet from your foundation and never onto a neighbor’s lot or into the sanitary sewer unless your city allows it.
- Outdoor pumps need a GFCI-protected outlet with a weatherproof in-use cover; hire an electrician if you need a new circuit.
- In cold climates, slope or bury the discharge line so it cannot freeze solid.
Standing water in a low yard, against a foundation or in a window well can soak the soil, kill grass and push moisture into your basement. An outdoor sump pump gives that water a place to collect and an automatic way out. This guide covers planning, digging, plumbing the discharge and safe wiring so your system works through every storm.
When Does an Outdoor Sump Pump Make Sense?
An outdoor sump is a good fit when water collects in a spot that cannot drain by gravity, such as a backyard depression, the bottom of a sloped driveway, an exterior basement stairwell or a deep window well. It also works as the collection point for a French drain that has no downhill outlet.
If water is coming into the basement through the floor or along the footing, an interior sump with perimeter drain tile is usually the better fix. If gutters overflow next to the house, start with clean gutters and downspout extensions; our guide on how to unclog an underground gutter drain pipe may solve the problem without a pump.
| Situation | Best Solution | Pump Needed? |
|---|---|---|
| Low yard spot, slope to street available | French drain to daylight | No |
| Low yard spot, no downhill outlet | Outdoor sump pit and pump | Yes |
| Window well or exterior stairwell floods | Drain to footing tile or small outdoor sump | Often |
| Water through basement floor or footing | Interior perimeter drain and indoor sump | Yes (indoors) |
| Overflowing gutters by the foundation | Clean gutters, extend downspouts 4 to 10 feet | No |
What Do You Need To Install an Outdoor Sump Pump?
- Sump basin: a perforated plastic basin, commonly 18 to 24 inches in diameter and about 24 to 30 inches deep, with a lid that can bear foot traffic.
- Pump: a submersible sump pump with a vertical or tethered float switch. A 1/3 horsepower pump handles many residential jobs; choose 1/2 horsepower for long or uphill discharge runs.
- Drainage materials: nonwoven geotextile filter fabric and washed 3/4-inch gravel.
- Discharge plumbing: PVC pipe sized to the pump outlet (often 1-1/2 inches), a check valve, a union or rubber coupling for easy removal, and fittings.
- Power: a GFCI-protected outdoor receptacle with an in-use (bubble) weatherproof cover.
- Tools: shovel, post-hole digger, level, tape measure, PVC saw, primer and cement, wheelbarrow.
How Do You Install a Sump Pump Outside Step by Step?
Step 1: Choose the Pit Location
Find where water actually pools after a storm and place the pit at that lowest point. Keep it several feet from the foundation so you are not drawing water toward footings, and plan a route for the discharge line to a lower outlet. Make sure you can reach an outdoor outlet without long extension cords.
Step 2: Check Rules and Call 811
Ask your city or county where sump water may legally go. Many municipalities ban sump discharge into the sanitary sewer, and most prohibit directing water onto a neighbor’s property or a public sidewalk. Call 811 at least a few business days before digging so buried utilities are marked.
Step 3: Dig the Pit
Dig a hole roughly 6 to 12 inches wider and deeper than the basin. The extra room lets you surround the basin with gravel. Pile soil on a tarp so you can reuse it to regrade or haul it away.
Step 4: Line the Pit and Add a Gravel Base
Line the hole with filter fabric, leaving plenty of excess to fold over the top later. Pour 2 to 4 inches of washed gravel in the bottom and level it. This base keeps the basin stable and lets water enter from below.
Step 5: Set and Backfill the Basin
Set the perforated basin on the gravel with its rim at or slightly above finished grade so surface dirt does not wash in. Fill around it with gravel, fold the fabric over the gravel, and top with a few inches of soil or decorative stone. If you are connecting a French drain, bring the perforated drain pipe into a hole cut in the basin side.
Step 6: Install the Pump and Float
Place the pump on a flat paver or the basin’s solid bottom so it does not suck up sediment. Position it so the float can rise and fall freely without hitting the basin wall. Set the float according to the pump manual so the pump does not short-cycle.
Step 7: Plumb the Discharge Line
Connect PVC pipe to the pump outlet with a check valve above the pump so water in the line does not drain back into the pit. Run the line to a storm drain inlet where allowed, a dry well, a rain garden or a pop-up emitter at least 10 feet from the house. Slope the line continuously toward the outlet, or bury it below the frost line in cold regions.
Step 8: Provide Safe Power
Plug the pump into a GFCI-protected outdoor receptacle with an in-use cover that stays weatherproof while the cord is plugged in. Route the cord through conduit or protect it from mowers and foot traffic. If you need a new outdoor outlet or circuit, hire a licensed electrician.
Step 9: Cover and Test the System
Fill the basin with a garden hose and watch the float lift and the pump start. Confirm water reaches the outlet and the pump shuts off cleanly. Secure the lid so children and pets cannot lift it.
Safety: Water and electricity are a dangerous mix. Never splice extension cords outdoors, never handle a pump that is plugged in and sitting in water, and never remove the ground prong from the plug. Use only a GFCI-protected outlet.
Where Should an Outdoor Sump Pump Discharge?
The discharge point matters as much as the pump. Common legal options include a curbside storm drain connection (often requires a permit), a dry well filled with stone, a rain garden, or a pop-up emitter that releases water on a lawn sloping away from buildings. Keep the outlet at least 10 feet from your foundation and away from septic drain fields and wells.
In freezing climates, a frozen discharge line can make the pump run against a blockage and burn out. Bury the line below frost depth, slope it so it fully drains between cycles, or add a freeze-protection fitting that lets water escape near the house if the line freezes.
Common Outdoor Sump Pump Mistakes
- No filter fabric. Silt and clay migrate into the basin and wear out the pump.
- Basin rim below grade. Surface runoff carries mulch and dirt straight into the pit.
- Skipping the check valve. The pump re-pumps the same water and cycles too often.
- Discharging too close to the house. Water loops back to the pit or into the basement.
- Using an indoor-only extension cord. It is a shock and fire risk outdoors.
If you still see damp walls after fixing outdoor drainage, inspect for wall cracks; our guide to repairing foundation cracks in concrete walls explains small repairs. For hidden water problems, see how to tell if you have a water leak underground.
How Do You Maintain an Outdoor Sump Pump?
Every few months, and before rainy season, pour water into the pit to make sure the pump starts and stops. Lift the pump out once a year, rinse the intake screen and clear debris from the basin bottom. Check the discharge outlet for leaves, ice or crushed pipe, and test the GFCI with its test and reset buttons. In regions with hard winters, some owners pull the pump in late fall if the pit stays dry until spring.
When Should You Call a Professional?
Call a drainage contractor if water covers a large area, the pit fills faster than a residential pump can keep up, or you need to tie into a municipal storm system. A licensed electrician should install any new outdoor circuit. If water is entering your basement or you see foundation movement, have a waterproofing specialist or structural engineer evaluate the home before relying on an outdoor pit alone.
Frequently Asked Questions
Can a sump pump be installed outside?
Yes. Outdoor sump pits are common for low yard areas, driveways, window wells and French drains with no downhill outlet. Use a perforated basin wrapped in filter fabric, a submersible pump with a float switch, a weatherproof GFCI outlet and a discharge line that carries water well away from buildings.
How deep should an outdoor sump pit be?
Most residential sump basins are about 24 to 30 inches deep, and the hole should be 6 to 12 inches deeper and wider than the basin for gravel. Go deep enough that the collected water sits below the area you want to keep dry, and keep the basin rim at or just above grade.
What size sump pump do I need for a yard?
A 1/3 horsepower submersible pump handles many yard and window well jobs. Choose a 1/2 horsepower model if the discharge line is long, runs uphill or the pit fills quickly in heavy rain. Check the manufacturer performance chart for gallons per hour at your vertical lift.
How do I keep an outdoor sump pump from freezing?
Bury the discharge line below your local frost depth or slope it so it drains completely between cycles. A freeze-protection fitting near the house lets water escape if the line ices up. In very cold areas, some owners remove the pump for winter when the pit stays dry.
Where can I legally discharge sump pump water?
Rules vary by city, but common options are a storm drain connection with a permit, a dry well, a rain garden or a pop-up emitter on your own lawn. Many places ban sump water in the sanitary sewer and prohibit sending it onto neighbors, sidewalks or streets. Check with your local public works department.
