Sump pump sizing Last reviewed June 30, 2026
Sump Pump GPH Chart: Capacity by Horsepower & Lift
By the WhatSize editorial team 4 min read Standards-reviewed
A 1/3 HP sump pump delivers ~3,000-4,000 GPH at 5 ft lift and ~1,800 GPH at 15 ft lift. A 1/2 HP delivers ~4,500-5,500 GPH at 5 ft and ~3,000 GPH at 15 ft. A 3/4 HP delivers ~6,000-7,500 GPH at 5 ft and ~4,000 GPH at 15 ft. Pick the HP that handles your peak inflow at your vertical lift.
How to read the GPH chart
GPH (gallons per hour) is the unit that tells you how much water a sump pump can move. Every pump has a curve that shows GPH at various vertical lift heights (head). The chart below shows typical GPH ratings for residential sump pumps at common lift heights (5, 10, 15, 20 ft).
Why lift matters: a 1/3 HP pump rated for 4,000 GPH at 0 ft lift may only deliver 1,500-2,000 GPH at 15 ft lift. Always read the manufacturer's performance curve for your actual lift height, not the zero-head number.
Your peak inflow is the highest rate water enters your sump pit. For a typical basement with occasional seepage, that's 200-500 GPH. For a basement in heavy-rain areas, it can be 1,000-3,000 GPH during peak storms. The pump's GPH at your lift must exceed peak inflow by at least 50% for cycling margin.
Top picks for this size
These Amazon-available picks meet the calculated spec. For region-specific or licensed contractor-installed options, consult a local professional. See our Disclaimers.
GPH chart by horsepower and lift
Residential sump pump GPH at lift height
| Pump HP | 5 ft lift | 10 ft lift | 15 ft lift | 20 ft lift |
|---|---|---|---|---|
| 1/3 HP | 3,000-4,000 | 2,400-3,200 | 1,500-2,200 | 800-1,200 |
| 1/2 HP | 4,500-5,500 | 3,500-4,500 | 2,500-3,500 | 1,400-2,000 |
| 3/4 HP | 6,000-7,500 | 5,000-6,000 | 3,500-4,500 | 2,200-3,000 |
| 1 HP | 8,000-10,000 | 6,500-8,000 | 4,500-6,000 | 3,000-4,000 |
Ranges shown are typical for major residential brands (Zoeller, Wayne, Liberty, Champion). Check your specific model's performance curve for exact GPH at your lift.
How to pick the right HP for your situation
- Measure your vertical lift: from pump outlet to discharge point (e.g., 8 ft to basement ceiling + 6 ft up the side of the house + 1 ft to the yard = 15 ft total dynamic head).
- Estimate your peak inflow: light seepage = 200-500 GPH; normal seepage = 500-1,000 GPH; heavy rain = 1,000-3,000 GPH.
- Find the HP that delivers at least 1.5× your peak inflow at your lift. (50% cycling margin.)
- Add battery backup if you live in storm-prone areas — see our battery backup guide.
Use our free sump pump calculator for your specific pit depth and conditions.
Frequently asked questions
How many GPH does a 1/3 HP sump pump deliver?
A typical 1/3 HP residential sump pump delivers 3,000-4,000 GPH at 5 ft lift, dropping to 1,500-2,200 GPH at 15 ft lift. Check the specific model's performance curve for the exact GPH at your lift height.
How many GPH do I need for my basement?
Match pump GPH at your lift to 1.5× your estimated peak inflow. For most basements with light to moderate seepage, a 1/3 HP pump (3,000-4,000 GPH at 5 ft lift) is sufficient. Heavy seepage or storm-prone areas need a 1/2 HP pump.
Is higher GPH always better?
For the same lift, yes. But oversized GPH means the pump short-cycles (turns on and off rapidly), which shortens motor life. The right size is 1.5-2× your peak inflow at your lift.
You might also need
More sump pump sizing guides
- What Size Sump Pump for a Basement? Complete Guide
- 1/3 HP vs 1/2 HP Sump Pump: Which Size Do You Need?
- Sump Pump Sizing for Heavy Rain Areas
- Sump Pump Battery Backup: What Size Do You Need?
- Sump Pump Installation Guide: Pipe Size, Check Valves & More
- Sump Pump Battery Backup Sizing + Runtime Chart
- What Size Sump Pump for a Crawl Space?
- 1/2 HP vs 3/4 HP Sump Pump: Which Do You Need?
- What Size Sump Pump for a High Water Table?
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