Well Water Flow Rate Calculator
Calculate your well's Gallons Per Minute (GPM) using the bucket test method.
Results
Flow Rate (GPM):
0.00
Hourly Yield (GPH):
0
Daily Yield (24h):
0
Status:
Checking…
Required Household GPM:
0.00
Enter your test details and click calculate to see your well's performance.
Understanding Well Water Flow Rate
The flow rate of your water well is one of the most critical metrics for homeowners relying on private water systems. Measured in Gallons Per Minute (GPM), it determines whether your water supply can keep up with the peak demand of your household, such as running a shower, washing machine, and dishwasher simultaneously.
How to Perform a Bucket Test
The simplest way to estimate your well's flow rate without expensive equipment is the "Bucket Test". This calculator is designed to process the data from this test.
- Preparation: Ensure no other water is running in the house.
- Location: Find a faucet close to the pressure tank (often a garden hose spigot). Bypassing water softeners or filters is ideal for an accurate raw flow reading.
- The Bucket: Use a container of known volume. A standard 5-gallon bucket is most common.
- Timing: Turn the water on full blast. Use a stopwatch to measure exactly how many seconds it takes to fill the bucket to the rim.
- Calculation: Input the volume and time into the calculator above.
What is a Good Flow Rate?
A "good" flow rate depends heavily on the size of your household and your water usage habits. However, general industry standards suggest:
| Flow Rate (GPM) | Classification | Suitability |
|---|---|---|
| Less than 3 GPM | Poor | Requires storage tanks or strict water conservation. Not suitable for modern households without augmentation. |
| 3 to 5 GPM | Fair/Average | Adequate for small families (2-3 people). Limit simultaneous water use. |
| 6 to 12 GPM | Good | Standard for most single-family homes (4 people). Can run multiple fixtures. |
| 12+ GPM | Excellent | Excellent supply. Suitable for large families and irrigation. |
Addressing Low Flow Rate
If your calculation shows a low flow rate (under 5 GPM for a family of 4), you may experience pressure drops during showers or appliance usage. Solutions include:
- Storage Tanks: Installing a large atmospheric storage tank allows the well to pump water slowly over 24 hours, building up a reserve for peak demand times.
- Hydrofracking: A process that injects high-pressure water into the well to open up new rock fissures and increase water access.
- Pump Upgrade: Sometimes the limitation is not the aquifer but an undersized or failing well pump.
Peak Demand Calculation
While the well yields a specific GPM, your home uses water in bursts. A general rule of thumb for calculating required GPM is to count the number of fixtures running simultaneously. A shower uses ~2.5 GPM, a toilet ~3 GPM, and a kitchen faucet ~2 GPM. If you need to shower while doing dishes, you need at least 4.5 to 5 GPM from your well.