As any seasoned traveler will tell you, a reliable water supply is the lifeline of your expedition. That’s where your trusty RV water pump comes into play – the indispensable device that keeps the water flowing and the adventures rolling. Yet, without proper priming, this hero can turn into a bit of a troublemaker, causing airlock headaches that no one wants to deal with during a camping trip.
But worry not! I’m here to share some expert insights and easy steps on how to prime an RV water pump with confidence and ease. By the end of this guide, you’ll have the know-how to handle any situation and keep your water system operating flawlessly.
With a well-primed pump, you’ll be all set to embark on unforgettable journeys, where the joy of discovery meets the comfort of home. So, let’s grab your tools and get ready to dive into the process of priming of an RV water pump.
How Does an RV Water Pump Work?
An RV water pump is a device used in recreational vehicles (RVs) to draw water from the onboard fresh water tank and distribute it throughout the RV’s plumbing system. It is responsible for delivering a steady flow of water to the faucets, showers, toilets, and other water outlets inside the RV.
critical component of an RV’s water system, ensuring that the occupants have access to clean water for cooking, cleaning, and personal hygiene while on the road. It allows RVers to enjoy the freedom of camping without relying on external water sources.
In addition to delivering water, some RV water pumps come with additional features such as adjustable flow rates, self-priming capabilities, and compatibility with accumulator tanks to regulate water pressure.
An RV water pump works by utilizing a diaphragm or impeller to create pressure that draws water from the fresh water tank and pushes it through the plumbing system of the recreational vehicle.
When a water faucet or any other water outlet inside the RV is opened, it creates a drop in pressure within the plumbing system. The RV water pump detects this pressure drop and automatically activates. As the pump starts running, it draws water from the fresh water tank through an inlet and into its chamber.
The diaphragm or impeller inside the pump moves back and forth, creating pressure that forces the water out of the pump and through the pipes to the desired water outlet. The pressure generated by the pump is what allows water to flow through the system and out of the faucets, toilets or shower heads inside the RV.
Once the water outlet is closed, the pressure in the plumbing system increases, and the pump senses this change. As a result, the RV water pump automatically shuts off to conserve power and prevent any unnecessary water flow.
The pump remains in standby mode until another water outlet is opened, starting the process again and providing a continuous supply of water on-demand.
Why Do We Need to Prime an RV Water Pump?
Priming is the process of removing any trapped air from the pump and plumbing to ensure that water can be efficiently drawn and circulated throughout the RV’s water system. It is essential to prime the RV water pump before its initial use or after it has been sitting idle for an extended period.
Priming an RV water pump is essential for several reasons:
Removing air trapped in the pump: When an RV water pump is not in use or has been sitting idle for a while, air can get trapped inside the pump and the plumbing system. If the pump is not properly primed, this trapped air can hinder the pump’s ability to draw water effectively from the fresh water tank.
Ensuring efficient water flow: Properly priming the RV water pump ensures that there are no airlocks in the system. Airlocks can disrupt the water flow and cause sputtering or reduced water pressure at the faucets and other water outlets inside the RV.
Preventing pump damage: If the RV water pump runs without being properly primed and without water flowing through it, it can cause the pump’s internal components to overheat or become damaged. Running the pump without water can lead to premature wear and shorten the pump’s lifespan.
Optimizing pump performance: Priming the RV water pump ensures that it is ready to function optimally when needed. A properly primed pump will draw water efficiently from the fresh water tank and deliver a steady flow of water to all the water outlets inside the RV.
Conserving water: When the pump is not properly primed, it may struggle to draw water, leading to wastage of water or inefficient water usage. Priming the pump helps conserve water by ensuring that it operates efficiently and delivers the right amount of water as needed.
Preventing air from entering the plumbing system: If there are air pockets in the plumbing system due to improper priming, it can lead to issues like gurgling noises or erratic water flow. Priming the pump and eliminating air pockets prevents such problems.

How to Prime an RV Water Pump: The Process
Priming an RV water pump is a straightforward process that any RV owner can do with a few simple steps. Follow these easy steps to ensure your RV water pump is ready to deliver a steady flow of water during your adventures:
Step 1: Gather the necessary tools
Before you begin, gather the tools you’ll need for priming the RV water pump. You’ll need a screwdriver, a pair of pliers, and a bucket of water. Having these tools on hand will make the priming process smoother.
Step 2: Check the fresh water tank
Make sure your RV’s fresh water tank is filled with an ample supply of water. The water pump needs water in the tank to create the necessary pressure for priming.
Step 3: Turn off the power
Before priming the RV water pump, it’s essential to turn off the power to the pump. Locate the switch or control panel inside your RV that controls the water pump and switch it off.
Step 4: Locate the pump’s Access Panel & Prime Port
Next, locate the access panel for the water pump. The access panel is usually located near the fresh water tank, often in a cabinet or under a seat. Remove the screws or fasteners securing the panel to access the water pump.
Once you have access to the water pump, look for the prime port. The prime port is a small screw or valve located on or near the pump. It’s typically labeled as “prime” or “pump prime.”
Step 5: Open a faucet
Before you start priming, open one of the faucets inside the RV. This will allow air to escape from the plumbing system as you prime the water pump.
Step 6: Pour water into the Prime Port
Take your bucket of water and carefully pour it into the prime port. This action will help remove any trapped air inside the pump and the plumbing system. Once you’ve poured water into the prime port, quickly close it to prevent water from splashing out.
Step 7: Turn on the power & let the pump run
Now that the prime port is closed and the water is inside the pump, it’s time to turn the power back on. Locate the switch or control panel for the water pump and switch it back on.
Allow the water pump to run for a few minutes. This will help the pump circulate the water throughout the plumbing system and remove any remaining air.
Step 8: Monitor the system for proper priming
After a few minutes of running the pump, check the faucet you opened earlier. If water is flowing smoothly and without sputtering, it means the pump is properly primed.
To ensure the entire system is free of air, check other water outlets like the shower and toilet. If water flows consistently from all outlets, the priming process is successful.
Step 9: Close the Faucet
Finally, close the faucet you opened earlier. The RV water pump is now primed and ready to provide you with a reliable water supply throughout your journey.
Signs that Your RV Water Pump Needs Priming
In fact, there are some signs to remind you that it’s time to prime your RV water pump. As an RV owner, it’s crucial to be aware of the signs and promptly prime your RV water pump when needed to ensures a reliable water supply during your travels.

- Sputtering Water: If you turn on a faucet or shower and notice the water sputtering or coming out in spurts, it’s a clear sign that there may be air trapped in the pump or plumbing system. Priming the pump will help remove the air and restore a smooth water flow.
- Low or No Water Pressure: When you open a faucet, and the water pressure is significantly lower than usual or there’s no water coming out at all, it could be due to air pockets in the water pump. Priming the pump will eliminate these airlocks and restore proper water pressure.
- Unusual Noises: If the water pump starts making strange noises, such as loud vibrations or rattling sounds, it might be struggling to draw water due to airlocks. Priming the pump can help alleviate these noises and ensure the pump operates quietly.
- Frequent Cycling: A water pump that constantly cycles on and off even when no water is being used could indicate air trapped in the system. Priming the pump will remove the air and reduce unnecessary cycling, which can save power and extend the pump’s lifespan.
- Inconsistent Water Flow: If the water flow from different faucets varies or fluctuates, it may be due to airlocks affecting certain parts of the plumbing system. Priming the pump will help balance the water flow and ensure consistent pressure throughout the RV.
- Difficulty Drawing Water: If the water pump struggles to draw water from the fresh water tank or takes longer to prime than usual, it could be a sign of air pockets in the pump. Priming the pump will ensure it operates efficiently and draws water without any delays.
- Loss of Prime: If you notice that the water pump loses its prime frequently, meaning it stops drawing water and requires priming more often than usual, it indicates an underlying issue with airlocks. Priming the pump properly will prevent frequent loss of prime.