“Water hammer” sounds like something you would use to fix an aquarium or build an underwater house. But for RV owners, a water hammer can sometimes pack a punch that you will want to avoid.
Avid RVers may be more familiar with the true definition of the term. It is the clatter or noise that your RV’s water pipes make when turning a faucet on/off or flushing a toilet. It is a very common complaint among RV owners and can not only be annoying but potentially damaging to sensitive fittings and pipes.
It would be convenient if there were a simple answer as to exactly what causes water hammer, as well as a simple answer as to how to fix it. Unfortunately, neither is the case.
Some RV manufacturers use less expensive pumps and connection methods to reduce cost, which can result in water hammer, either from chattering pipes or floor vibration. Others say that jack hammering (as it is also called) is due to the pulsation of water inside the campground water supply pipes, or that it is created by RV water pumps when they run, which causes the hard piping of the RV water supply systems to vibrate against interior walls and cabinets. And yet others claim that air in the system is the culprit - an aftershock caused by trapped air within the water pipes that compresses when running water to a particular faucet that is rapidly turned off (or sometimes on).
With that said, our research shows that the two most commonly cited causes of water hammer are air in the system and too-high water pressure. There are some inexpensive fixes for these issues, but before trying them, here are some possible remedies that can be tried without spending a cent. For issues with your internal pump and fittings, here are some suggestions:
- Shut off the water supply and open all faucets to release all pressure and trapped air; then shut off the faucets and turn it back on.
- Sometimes water pumps can cycle on and off rapidly (less than 2 seconds) during low flow conditions, which can cause pulsations in the water system. To determine if adjustment is necessary, turn a faucet on to a lower-than-average flow of water. The pump should cycle, but its off time should be 2 seconds or longer. If the pump is cycling rapidly, and has an adjustment screw, increase the setting by turning the adjustment screw on the pump clockwise (one turn maximum) until the pump operates with at least 2 seconds of off time. Be sure to follow the manufacturer’s instructions for proper adjustment.
- The pump itself may not be securely installed. Re-securing the pump and adding rubber washers will help to isolate the pump vibrations from the floor.
- Rattling water pipes. Turn on the pump and have a friend open and close any faucet while you try to locate the rattling noise. Wrap the pipe where it rattles against the cabinet or flooring, with 1/2-inch foam insulation. Repeat until you have insulated all rattling pipes.
These suggestions will help when the problem is on board and is just an annoyance, but the real trouble can be linked to water pressure spikes. A little-known fact is that water is not compressible; consequently, under pressure and momentum, water can slam into fittings with the force of a hammer. Thus, “water hammer.”
According to the RV Share blog, water pressure in campgrounds can be finicky. It can be extremely high, extremely low, or fluctuate between the two. On top of that, the pressure in a campground can change from one site to the next, or even from one season to the next. Plus, pressure can fluctuate substantially depending on how many RVers and campers are using the system at any one time.
Using a water pressure regulator right at the spigot can go a long way towards protecting the overall RV versus just protecting the plumbing after the pump. RVs are built of strong but lightweight materials that do not mix well with water, such as particle board that can swell and cause warping. A serious pressure spike can not only damage filters and blow off fittings causing flooding/water damage - especially problematic if the leak occurs while the owner is away – but can also wreak structural havoc in all parts of the RV.
The proper RV water pressure regulator location is between the water source and the freshwater hose (or inline filter, if you are using one). Simply twist the regulator onto the spigot and connect the other side to the water hose or inline filter. A water pressure regulator will keep the water pressure just right for your RV (newer vehicles should stick to around 60 psi; older models around 50 psi).
The issue of a water hammer is not simply the noise, although it can be annoying. It’s a problem that can cause serious damage not just to plumbing but to all parts of your RV. A little attention to the problem – as well as the regular use of a water pressure regulator at your water source – can nip this problem in the bud.