Burying a Sump Pump Discharge Pipe: Fittings, Slope, and Dry Wells

A homeowner wants to bury a 2-foot PVC sump pump discharge pipe to move water 15–20 feet from the house, ending in an underground gravel-filled basin. Questions include bend types (90° vs 45°), pipe sizing, and commercial kits.

Design Recommendations

• Bends: Avoid 90° elbows; use two 45° elbows or long-sweep 90s to reduce friction and clogging risk.
• Pipe size: Upsize to 3" or 4" diameter (corrugated drain pipe works well) to handle peak flow and reduce velocity.
• Slope: Maintain at least 1/8" per foot fall away from the house.
• Dry well: Excavate a 3'×3'×3' pit, line with landscape fabric, fill with clean washed stone (1.5"–3"). A perforated basin or commercial dry-well kit (e.g., PolyLok) simplifies installation.
• Freeze protection: In cold climates, bury below frost line or use a freeze-resistant pop-up emitter at the terminus.

Commercial Kits

Search for "pop-up emitter kits" or "dry well kits" at home centers or suppliers like NDS, PolyLok, or Rain Bird. These include the emitter, basin, and fittings.

Ensure the discharge point directs water away from foundations and neighboring properties. Check local codes for discharge regulations.