Private well and septic: calculators and guides
For houses on their own well and septic. Calculators that do the sums for pumps, pressure tanks, softeners and septic tanks, and fault guides that work through the system in order.
No water right now? Check these three first
- The pump breaker. If it has tripped, reset it once. If it trips again, stop: that points to a wiring, cable or motor fault.
- The pressure gauge at the tank, pump silent. Below the cut-in pressure (often 20, 30 or 40 psi) and the pump isn't running: suspect power, the pressure switch or the control box.
- Pump running but the pressure won't rise. Suspect a jet pump that lost its prime, a stuck check valve, a leak, or a well that has run low. Don't let it run on.
What’s wrong? Pick what you see
No water. Look at the pressure gauge on or next to the pressure tank. Which is it?
Find it by the problem
| No water at the taps | No water from the well: checks in order |
|---|---|
| Pump won’t shut off | Pump troubleshooting |
| Pump clicks on and off every few seconds | Pump troubleshooting |
| Low or up-and-down water pressure | Pump troubleshooting, switch settings |
| Faucets spit air | Pump troubleshooting |
| Breaker keeps tripping, or pump hums | Pump troubleshooting |
| Jet pump lost its prime | How to prime a jet pump |
| Sand or grit in the water | Pump troubleshooting |
| Orange, red or brown stains | Iron in well water |
| Rotten-egg smell | Treatment by test result |
| Got a lab report back | Check your results |
| Haven’t tested in a year or more | How to test well water, labs in your state |
| Pump needs replacing | What it costs, what size |
| Power is out | Generator size for a well pump |
| Septic due for pumping? | How often to pump |
Calculators
| Tool | What it works out |
|---|---|
| Septic pumping & tank size | Years between pumpings; minimum tank size by bedrooms |
| Water softener size | Grain capacity, size class and salt per year |
| Pressure tank size | Tank volume and drawdown for your pump and switch |
| Well pump size & total dynamic head | Flow needed and total dynamic head |
| Well pump wire size | Smallest wire size for your motor and cable run |
| Well water test results | Each result against EPA limits, and what to do first |
How a private well system fits together
- Service panel and pump breaker Feeds the pump circuit at 115 V or 230 V.
- Control box Starting parts for 3-wire single-phase pumps; 2-wire pumps have none.
- Pressure switch Starts the pump at cut-in and stops it at cut-out.
- Pressure gauge The first thing to read when water stops.
- Pressure tank Stores water under an air charge between pump starts.
- Water treatment (if fitted) Filters or softener, chosen from a lab test.
- Pitless adapter and buried line Where water leaves the well casing underground.
- Drop pipe and check valve Carry water up and hold pressure when the pump stops.
- Submersible pump and motor Sized for flow and total dynamic head.
- Static and pumping water levels Water level at rest, and lower while the pump runs.
About this site
We build the calculators, compare the published tables side by side where makers and states disagree, work the examples and draw the diagrams. The figures behind each tool and guide are listed at the bottom of its page. We are not licensed well, septic or electrical contractors, and pages say when a job needs one. Who we are and how the site makes money.