Why you need an RV water pump check valve

Boltigen TK

RVs have a pump for water supply whenever the RV isn't connected to city water. A check valve is usually connected to the water pump outlet to prevent backflow to the pump. This article discusses the importance of having a check valve in an RV water pump, the main issues these valves face, and how to fix them.

What is an RV water pump?

A recreational vehicle (RV) has basic amenities like a sink, shower, faucets, and a freshwater storage tank. A pump moves the water from the tank to the devices for use. The pump is typically a 12 V DC pump that wires directly to a 12 V power supply. 120 V AC pumps are available and are installed for RV air conditioners. The RV can also connect to a city water supply that transports water directly to these devices through pipes.

An RV pump system usually comes with the pump, the fittings required to install the pump to the RV’s water system, and wires to connect the pump to the RV’s electrical circuitry. The pump works on demand, meaning there is a pressure switch at the head of the pump. When an RV faucet opens, it signals the pump to turn on and send water. When the faucet closes, the pump turns off.

RV water pumps come in a wide range of sizes. The appropriate pump for an RV depends on the size of the RV, water flow rate, and the pressure required.

  • RV size: In the case of a massive forty feet (12 m) RV, it’s wise to opt for a bigger pump, whereas a small pump would suffice for a small-scale RV.
  • Flow rate: Flow rate is calculated in gallons per minute (gpm) or liters per minute (lpm). It is essential to know the necessary flow rate for the RV’s water system before selecting a pump.
  • Pressure: Understand the necessary static pressure (no water is being used) and operational pressure of RV’s water system to choose a pump that best suits the requirements.

RV water pump check valves

Check valves work by allowing fluid to flow in only one direction. An RV water pump check valve connects to the pipe/hose going out of the RV’s water pump. When the RV connects to the city water supply, the water pump check valve prevents the water from flowing into the pump and eventually into the freshwater tank. Specific water pumps come with an inbuilt check valve. For example, in some models, the check valve may be in the pressure switch head. The check valve position varies by pump manufacturer.

Choose a check valve according to the back surge pressure rating that needs to be safeguarded against by the device. Also, the check valve material must be compatible with water. PVC (Polyvinyl chloride), brass, and stainless steel are commonly used to make the check valve housing for RV water pumps.


Periodic investigation of an RV water pump check valve helps conserve water and stop leaking before it causes damage to the adjoining areas. The check valve may get dislodged and remain stuck open, causing the city water connection to flow back into the pump and the freshwater storage tank, resulting in an overflow. This can happen for multiple reasons:

  1. Having the pump on while connected to city water.
  2. RV running on city water with extremely high water pressure.
  3. RV water pump failure.

A common method to fix the check valve includes the following steps:

  1. Disconnect the city water supply from the RV.
  2. Turn on the water pump.
  3. Run a faucet and drain the water for 10-15 seconds.
  4. Turn off the water pump.
  5. Turn on the city water supply.
  6. Run a faucet and drain the water for 10-15 seconds.
  7. Repeat the above steps 2-3 times to reset the check valve.
  8. Replace the check valve if it is still faulty.


A faulty RV water pump check valve can allow all of the freshwater to drain and prematurely end a campout when dry camping far away from a potable water source. RV water pump check valves aren't difficult to take care of and maintain. From proper installation to regular maintenance like inspecting water lines, pump straining, sanitizing the whole system, winterizing, and annual inspection, one can ensure the pump runs effectively for a long time.

Check valve installation

Install the check valve at the RV water pump’s outlet. An arrow on the valve indicates the flow direction; ensure to install the valve accordingly. Read our article on check valve installation for more details on check valve installation and maintenance.

Conducting annual inspection

An annual RV water pump and check valve inspection involve the following steps:

  1. Filter cleaning: Cleaning the filter on the pump's inlet side is crucial to avoid debris clogging the pump and the check valve. Most pumps have filters, and in the case of a pump not having a filter, one can be readily purchased and installed.
  2. Removing any accumulated material: The check valve can collect scale, algae, and debris, leading to damage. Clean the internal parts of the valve periodically.
  3. Sanitization and desalination: Sanitize and desalinate the whole water system to help disinfect the entire freshwater system.
  4. Installing a pump strainer: A pump strainer between the fresh water tank and the RV pump can help prevent debris, dust, and other particles from entering the pump and damaging the check valve.
  5. Visually inspecting the water lines: A visual inspection can help identify for repair any damages, leaks, punctures, and damages.
Back to blog