Faucet Drip Calculator
Enter your drip speed and water cost to see exactly how many gallons and dollars your dripping faucet wastes per day, month, and year — and when fixing it pays for itself.
Step 1 — Drip speed
Step 2 — Your situation
Step 3 — Hot or cold water?
How to fix a dripping faucet — cost vs. payback
Drip fixed but faucet worn out? Replacing an old 2.2 GPM faucet with a WaterSense 1.5 GPM model saves an additional 700+ gallons per year on top of stopping the drip. Browse our full faucet reviews and comparisons.
Browse Faucet Reviews →Frequently Asked Questions
The Real Cost of a Dripping Faucet: What the Numbers Mean
The EPA's WaterSense program estimates that dripping faucets across the United States waste approximately 1 trillion gallons of water annually — enough to supply 11 million homes for a year. That aggregate figure is built from millions of individual drips that homeowners regard as minor inconveniences. A single slow-dripping faucet at 1 drip per second wastes approximately 3,000 gallons of water per year — enough for 8 full showers or 10 loads of laundry. The drip rate matters enormously: going from a slow drip to a trickle multiplies waste by roughly 9 to 10 times.
The EPA Drip Formula: 15,140 Drips Per Gallon
The EPA's standard for faucet drip calculations is 15,140 drips per gallon. This figure was established through controlled testing and is the basis for the EPA's WaterSense Drip Accumulator tool. The formula chain from drip rate to annual cost:
- Drips per day = drips per minute × 60 × 24
- Gallons per day = drips per day ÷ 15,140
- Annual gallons = gallons per day × 365
- Annual cost = annual gallons × local water rate per gallon
The US average water cost is approximately $0.005 per gallon (EPA, 2023 data), but in drought-prone California and Arizona, water can cost $0.012–$0.020 per gallon including sewer charges — making faucet drips a significantly larger financial issue in those markets. A slow drip in Phoenix costs 2–3 times as much as the same drip in a low-cost rural market.
The Drip Rate Table: Gallons Lost Per Scenario
| Drip Rate | Drips/Day | Gal/Day | Gal/Year | Cost/Year (US avg) |
|---|---|---|---|---|
| 1 drip/sec (slow) | 86,400 | 5.7 | 2,082 | $10.41 |
| 60 drips/min (1/sec) | 86,400 | 5.7 | 2,082 | $10.41 |
| 2 drips/sec (steady) | 172,800 | 11.4 | 4,161 | $20.81 |
| 4 drips/sec (fast) | 345,600 | 22.8 | 8,322 | $41.61 |
| Trickle (~9 ml/sec) | ~800,000 | ~52.8 | ~19,272 | ~$96 |
Hot Faucet Drips: The Hidden Energy Cost
A dripping hot water faucet has a cost that cold-drip calculations miss entirely: the energy cost to heat the wasted water. The formula is based on the Btu requirement to heat water from inlet temperature to delivery temperature. Using 8.33 BTU per pound of water, a 90°F temperature rise (40°F inlet to 130°F delivery), and natural gas at $1.20/therm (100,000 BTU):
For a moderate hot water drip wasting 5,000 gallons per year: heating cost = (5,000 gal × 8.33 lbs/gal × 90°F ÷ 100,000) × $1.20 = approximately $45/year in gas heating alone. For electric water heaters at $0.16/kWh, the same drip costs approximately $80/year in heating — on top of the water cost. A hot drip at a moderate rate can cost $80–$120/year total, making faucet repair a financial priority, not just an environmental one.
Why Drips Worsen Over Time
Faucet drips are progressive failures — they do not stay at the same rate. In compression faucets, a worn rubber seat washer compresses less with each use, allowing slightly more water past with each drip cycle. Mineral deposits from hard water accumulate on worn cartridges and O-rings, preventing the clean seal that stops water flow. What begins as 10 drips per minute becomes 30, then 60, then a continuous trickle — typically over 6 to 18 months. This is why drips caught early are cheap to fix ($5–$15 in parts) while drips left for 2+ years often require cartridge replacement rather than just an O-ring swap.
The Three Faucet Repair Scenarios
Most faucet drip repairs fall into one of three scenarios based on severity and faucet age:
- Scenario 1: Young faucet (under 10 years), first drip: Almost always a single worn O-ring or seat washer. Parts cost $2–$15. DIY repair in 20–30 minutes. No plumber needed.
- Scenario 2: Mid-age faucet (10–15 years), recurring drip: Cartridge wear is the likely cause. Replace the full cartridge ($15–$40). Payback typically within 2–6 months versus the water waste cost.
- Scenario 3: Old faucet (15+ years), multiple drip events: At this point, part availability may be limited, and replacement is often more cost-effective than repair. A new WaterSense 1.5 GPM faucet costs $40–$200 and provides 20+ years of reliable service. The incremental water savings from the efficiency upgrade add to the payback calculation.
When to Replace Rather Than Repair
Three conditions make replacement more practical than repair: (1) The faucet is more than 15 years old and has had multiple drip events — the full cartridge body or valve seat may be worn beyond what part replacement can fix. (2) Replacement cartridges for your specific model are discontinued or cost more than $50 — at that price, a new faucet at $60–$150 is a better value. (3) The faucet has cosmetic damage (corrosion, finish failure, loose handles) alongside the drip — replacing solves all issues simultaneously and resets the fixture's service life. Modern WaterSense faucets at 1.5 GPM also save 700+ gallons per year vs. the 2.2 GPM standard they replace — an additional financial benefit that accelerates the overall payback on replacement vs. repeated repair.