Pressure at rest is only one observation. Useful supply depends on pressure while water flows through the actual route.
1. Keep pressure, head and flow separate
Pressure is force per area; head expresses that pressure as a height of fluid. Flow describes volume per time. A gauge can show high static pressure even when a restriction prevents useful flow.
The pressure-to-head calculator converts units for a stated fluid density. Pump selection still requires the total head at the design flow, including elevation and every relevant loss.
2. Measure static and dynamic conditions
Record pressure with all outlets closed, then repeat while a measured flow runs. Note the test location, pump state and pressure-switch cycle. A single reading without flow and location is hard to diagnose.
Repeat representative tests at the source, after treatment equipment and near the most demanding outlet where safe test points exist. A large difference helps locate where pressure is being consumed.
3. Match demand to source, storage and controls
A well system may combine borehole yield, stored water, pump capacity and a pressure tank. Compare short peak demand with the pump and storage, then compare daily demand with sustainable source yield.
Penn State Extension notes that storage can help a lower-flow source meet periods when household use exceeds source flow, while seasonal groundwater and drought still affect reliability.
Penn State Extension · Planning private water needs ↗4. Diagnose the whole pressure path
Check valves, filters, softeners, small fittings, long pipe runs and elevation before blaming the pump. Record the clean-filter and dirty-filter pressure difference to support a maintenance rule.
Have pressure vessels, relief devices, electrical controls and potable-water connections inspected by qualified professionals. Do not adjust a pressure switch beyond equipment ratings.
A useful pressure test record
| Reading | Condition | What it can reveal |
|---|---|---|
| Source static pressure | No flow | Control range and stored pressure |
| Source dynamic pressure | Known flow | Pump operating condition |
| After-treatment pressure | Same known flow | Treatment loss |
| Remote outlet pressure | Same known flow | Distribution and elevation loss |
| Flow rate | At every comparison | Makes readings comparable |
Worked example
Convert 3 bar into water head
Assume water density is 998 kg/m³.
Head = 300,000 / (998 × 9.80665) = 30.65 m Pressure = 3 × 14.5038 = 43.51 psi
This conversion does not add pipe friction or elevation. Those terms belong in the pump-system calculation.
What to have ready
- Pressure gauge and measured flow
- Test-point elevations
- Pump curve and pressure-switch settings
- Filter and equipment pressure limits
Common mistakes
- Diagnosing supply from static pressure alone.
- Confusing maximum pump head with the operating point.
- Adjusting controls without checking vessel and pipe ratings.
Reference check: 5 September 2026. Sources include US public agencies. Principles are general; regulations and design values must be checked where you live.Worked examples use stated hypothetical inputs.