Recommended Pump
330 GPH
Wattage
8W
Monthly Cost
$0.75
Height water must be pumped from reservoir to top
Leave at 0 to use the standard formula (100 GPH per ft)
Total length of tubing from pump to outlet
100 GPH × 3 ft head = 300 GPH
Based on $0.13/kWh national average
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Inputs
Result
Base GPH = 100 × 3 ft = 300 GPH. Tubing friction = 10 ft × 10%/10ft = 10%. Final GPH = 300 × 1.10 = 330 GPH. At ~0.025 W/GPH, minimum wattage = 8W.
Inputs
Result
Base GPH = 12" × 150 GPH/inch = 1,800 GPH. Tubing friction = 15 ft with 3/4" tubing at 6%/10ft = 9%. Final GPH = 1,800 × 1.09 = 1,962 GPH.
Inputs
Result
Base GPH = 500 gal ÷ 2 hr turnover = 250 GPH. Tubing friction = 10 ft at 10%/10ft = 10%. Final GPH = 250 × 1.10 = 275 GPH.
The standard rule is 100 GPH per foot of head height. A 3-foot fountain needs at least 300 GPH. Add 10% per 10 feet of tubing for friction loss. Always buy a pump slightly larger than calculated since you can restrict flow with a valve.
For waterfalls, you need 150 GPH per inch of spillway width. A 12-inch-wide waterfall needs 1,800 GPH. For a thin sheet effect, use 100 GPH per inch. For a heavy cascade, use 200 GPH per inch of width.
| Spillway Width | Light Sheet | Standard | Heavy Cascade |
|---|---|---|---|
| 6 inches | 600 GPH | 900 GPH | 1,200 GPH |
| 12 inches | 1,200 GPH | 1,800 GPH | 2,400 GPH |
| 18 inches | 1,800 GPH | 2,700 GPH | 3,600 GPH |
| 24 inches | 2,400 GPH | 3,600 GPH | 4,800 GPH |
A pond pump should turn over the entire pond volume every 2 hours. A 500-gallon pond needs a 250 GPH pump at minimum. For ponds with fish, turn over every 1 hour instead. Add head height and friction loss on top of the base calculation.
A small fountain pump (100–200 GPH) uses 3–6 watts, costing about $0.30–$0.60 per month running 24/7 at $0.13/kWh. A large waterfall pump (1,500+ GPH) uses 40–80 watts, costing $3.80–$7.60 per month.
| Pump Size | Watts | Monthly kWh | Monthly Cost |
|---|---|---|---|
| 100–200 GPH | 3–6W | 2–4 kWh | $0.30–$0.60 |
| 300–500 GPH | 8–13W | 6–10 kWh | $0.75–$1.25 |
| 800–1,200 GPH | 16–24W | 12–18 kWh | $1.50–$2.30 |
| 1,500–3,000 GPH | 40–80W | 29–58 kWh | $3.80–$7.60 |
Use 1/2" tubing for pumps under 300 GPH, 3/4" for 300–600 GPH, and 1" for 600–1,200 GPH. Undersized tubing increases friction loss and reduces actual flow. Wider tubing is always better if it fits your setup.
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Last Updated: Mar 26, 2026
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