A quick note before we start: this guide is most relevant if you live in a smaller apartment building, duplex, or converted house that relies on a private well rather than municipal water — this is uncommon in large apartment complexes, but it does happen in smaller multi-unit buildings, especially in rural or semi-rural areas. If your building uses city water, you won’t need this guide; check our piece on showering during a power outage instead, which covers municipal water systems.
Why Well Pumps Need Priming After a Power Outage
Well pumps rely on continuous electric power to maintain pressure in the system. When power cuts out, air can enter the pump and pipes, which causes the pump to lose its “prime” — meaning it can spin without actually moving water, even once power is restored.
How to Prime a Well Pump, Step by Step
- Turn off the pump’s breaker before doing anything else, for safety.
- Locate the priming plug on top of the pump housing — it’s usually a small bolt or cap you can remove by hand or with a wrench.
- Remove the plug and pour water into the priming hole until it’s completely full. This is the step that actually restores the seal needed for the pump to draw water properly.
- Replace the plug and make sure it’s snug, but don’t overtighten.
- Turn the breaker back on and run a faucet to check for steady water flow and pressure.
- If it sputters or runs dry, turn it off, repeat the priming process — sometimes it takes two attempts for the air to fully clear.
When to Call a Professional Instead
If the pump won’t hold prime after 2–3 attempts, or you hear unusual grinding or knocking sounds, stop. Continuing to run a pump that won’t prime can damage the motor, turning a simple fix into an expensive one. A well technician visit is far cheaper than a new pump.
Frequently Asked Questions
How do you know if your well pump needs priming after a power outage?
If your faucets sputter, produce no water, or only weak airy bursts after power is restored, your well pump has likely lost its prime. This is normal after sudden power loss and doesn’t usually indicate a deeper mechanical problem.
How many times can you try to prime a well pump before calling a professional?
Two to three attempts is the general rule. If the pump still won’t hold prime after that, or you hear grinding or knocking sounds, stop and call a well technician — continuing to run it can damage the motor.
If This Happens Often
If your building loses power regularly enough that this is a recurring chore, it’s worth knowing what these outages are actually costing you in time, spoiled food, and hassle. Our free Power Outage Cost Calculator adds it all up in under a minute.
Related Reading
- Free 27-Item Apartment Emergency Checklist
- Generator Size Finder — useful if frequent outages affect your water pump specifically