What Is a Freshwater Pressure Pump?
An automatic pump that delivers fresh water from the tank to the taps under pressure - the onboard equivalent of domestic mains-water comfort.
A freshwater pressure pump draws water from the tank, pressurises the line, and cuts in automatically when pressure drops (when a tap is opened). All onboard freshwater comfort depends on it, and the way it behaves is a good health check for the system.
The table below shows the most common symptoms.
Freshwater pressure pump symptoms
Symptom | Possible cause |
|---|---|
Intermittent cutting in with the taps shut | A small leak in the line, or the non-return valve is passing |
Runs continuously but won't build pressure | Tank empty, air on the suction side, or a blocked filter |
Pulsing, uneven flow | Accumulator pressure is low, or the diaphragm is worn |
A pressure pump that starts up now and then with all taps closed is telling you there is a leak somewhere in the line; that 'tick-tick at night' is the classic first sign of a freshwater leak.
Two habits prevent most problems: clean the pump's suction strainer once a season and switch the pressure pump off when leaving the boat. A leak when nobody's aboard will empty the tank into the bilge if the pump is left on. Over winter, drain the system completely; a pump body that has frozen is usually beyond repair.