How long to run your pool pump
One turnover of a 15,000-gallon pool at 40 gallons per minute (gpm) takes about 6.3 hours. That is a good daily starting point.
Always follow your product’s label directions. Pool and spa chlorine, bromine, shock and algaecides are EPA-registered pesticides: use products labeled for pool or spa use, and don’t swim or soak until levels are within the limit on your product’s label. If this page and a label disagree, the label wins.
On this page (7 sections)
About these numbers. The pump, heater, and cost formulas on this site are plain physics and arithmetic, but they are not yet covered by our tested reference cases the way the chemistry formulas are. The default 40 gpm flow is an example value, not a typical pump. Read your real flow from a flow meter or your pump's performance curve.
Calculator: gallons, flow (gpm), turnovers
A turnover means a volume of water equal to the whole pool has passed through the filter once. Hours per turnover = gallons ÷ gpm ÷ 60. Enter your pool size, your pump's flow in gpm, and how many turnovers you want per day. Don't know your gallons? The pool volume calculator works from your pool's shape and depth.
| Pool size | 20 gpm | 30 gpm | 40 gpm | 60 gpm |
|---|---|---|---|---|
| 5,000 gal | 4.2 h | 2.8 h | 2.1 h | 1.4 h |
| 10,000 gal | 8.3 h | 5.6 h | 4.2 h | 2.8 h |
| 15,000 gal | 12.5 h | 8.3 h | 6.3 h | 4.2 h |
| 20,000 gal | 16.7 h | 11.1 h | 8.3 h | 5.6 h |
| 30,000 gal | 25 h | 16.7 h | 12.5 h | 8.3 h |
Flow drops as the filter gets dirty, so on a dirty-filter day a real turnover takes longer than the table shows.
Why "one turnover" is a starting point, not a rule
Advice on pump hours ranges widely, and the sources behind it have different goals:
- The residential pump guidance summarized by the U.S. Building America Solution Center (from ANSI/APSP/ICC-15) says to turn the pool over at least once every 24 hours, and that turnover time should not be shorter than six hours in normal operation.
- The U.S. Department of Energy suggests cutting filtration to 6 hours a day and adding half an hour at a time until the water looks clean. In a Florida study it cites, most owners who pumped under 3 hours a day were still happy with their water.
- Salt pool makers tie run time to chlorine: Hayward says to run the pump long enough for all the water to pass the filter each day, and longer if chlorine demand is high, because the cell works only when water flows.
What circulation actually does is mix chemicals and pass water through the filter. The DOE notes that longer pumping does not by itself stop algae. Sanitizer and brushing do. So start at one turnover, watch clarity and chlorine for a week, then shorten or lengthen in half-hour steps. Several shorter cycles through the day can keep the surface cleaner than one long block.
Variable-speed pumps
Pump power falls much faster than flow. ENERGY STAR and the Building America guide both state the general rule: halve the speed and the pump uses about one-eighth the power. Half speed also moves about half the water, so one turnover takes twice as long. For the same turnover, the result is about one-quarter of the energy (1/8 × 2).
A worked example from the Building America guide: a 1.5 hp pump at 3,450 rpm draws about 2,000 watts. Slowed to 2,400 rpm (about 70% speed), it drew 593 watts. At 70% speed, 8 hours of full-speed flow takes about 11.5 hours. That is why the standard advice for variable-speed pumps is to run slower for longer, and save high speed for vacuuming, spa jets, or a solar heater.
Energy cost per month
Monthly cost = watts ÷ 1,000 × hours per day × 30 × your price per kWh. The table uses the wattages above and an example rate of $0.17 per kWh. Your bill shows your real rate.
| Pump setting | Hours a day | kWh a month | Cost a month |
|---|---|---|---|
| 2,000 W (single speed) | 6 | 360 | $61.20 |
| 2,000 W (single speed) | 8 | 480 | $81.60 |
| 2,000 W (single speed) | 12 | 720 | $122.40 |
| 593 W (variable speed, 2,400 rpm) | 12 | 213.5 | $36.29 |
Wattages from the Building America Solution Center example; your pump's label or controller shows its own watts.
For comparison, the DOE estimates a pool pump can cost as much as $270 a year and calls it possibly a home's second-largest electricity user. If you also heat the pool, the pool heater cost calculator estimates the other big energy cost.
When to run more (heat, algae, shock)
- Algae or shocking: run 24 hours a day until the water is clear and chlorine holds overnight. See the green pool fix.
- Adding chemicals: keep the pump on while you add them and for a while after, so they mix.
- Heat waves and heavy swimming: chlorine demand and debris both increase.
- Salt pools: if free chlorine (FC) falls at 100% output, you need more pump hours, not only a higher output setting.
- Opening day: run continuously until the water is clear, then reduce the hours.
A full weekly routine, including when to clean the filter, is in the pool maintenance schedule.
FAQ
How many hours a day should a pool pump run?
Start with one turnover: gallons ÷ gpm ÷ 60. For a 15,000-gallon pool with a 30–40 gpm flow, that is about 6–8 hours. Then adjust in half-hour steps by how clear the water stays and whether chlorine holds. Variable-speed pumps run longer at low speed for less energy.
Should my pool pump run all the time?
Not usually. Continuous running makes sense while you clear algae or after opening, and some variable-speed owners run a low speed around the clock. A single-speed pump running 24 hours a day uses four times the energy of the same pump at 6 hours. ENERGY STAR puts the savings from cutting 24 hours to 6 at 75%.
Sources
- U.S. DOE Energy Saver, Choosing, installing and operating an efficient swimming pool pump (archived copy, May 2026): energy.gov via web.archive.org
- Building America Solution Center (PNNL), Variable-speed pool pumps: basc.pnnl.gov
- ENERGY STAR, Pool pumps: energystar.gov
- Hayward, AquaRite manual (pump hours for salt pools): PDF