Forum Discussion

Singleminded's avatar
Singleminded
Explorer
Mar 10, 2017

Water 'Hammering' issue

Need some help with a weird problem.....!

Background:

We're in a campground (which we've been in for the past three months) in a 2016 Winnebago TT hooked up to the 'city' water supply. We haven't changed anything in the water supply set up....(other than the filter two months ago) and do not have a pressure regulator hooked up in line. (haven't needed one....campground water pressure is very stable)

After flushing the toilet.....When we depress the foot pedal further to allow some water to build in the bowl, we get very loud 'hammering' sound from the rear (junction box, water inlet location)!

None of the other water sources (kitchen sink, bathroom sink & shower) have the same problem....when flowing water, no hammering!

Any suggestions would be appreciated!
  • Get a water regulator the toilet is not designed for the water pressure going to it the valve will eventually fail
  • In the meantime try pinching down on the valve on the post to cut down the flow. May not make a difference but there is no cost to try it.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Ok, IN an RV there are TWO causes of "Hammering" not one like in a sticks and bricks

    The first (Never heard it in my RV) is caused by the physics of what happens when you CLOSE a valve. this is called Water Hammer and the advice of the others on this issue is dead on.. The "Arrester" is nothing more than an air chamber that absorbs the Hammer.

    The other source which is unique to RV's is the on-board fresh water pump.
    This will HAMMER when water is flowing.. The Toilet (And Shower) are the major flow items in the RV.. So if the city water inlet is partially clogged or if the city water pressure is low or if there is any "issue" with city water that limits flow such as a aging pressure regulator.. The on board pump, if powered on (Switch is on) may engage and it can Hammer. even with flex lines to/from it it can hammer... It is, after all, a jack hammer.
  • Thanks all!

    I've ordered a water hammer arrestor from Amazon (cheap!) with same day delivery....so it will be installed no later than late tonight....I'll report back on the results! (I'll also check for a lose clamp!)
  • Check for a broken clamp in the area of the noise allowing the pipe to float free. If it just started with no change in water pressure, I would suspect this.
  • I got the same deal on my commode. I think it is/may be a function of the valve in the commode.
  • RoyB's avatar
    RoyB
    Explorer II
    Search google for water hammer arrester... then select images... lots of photos on what a water hammer idea looks like...

    I bet one of those small size 2-Gallon Expansion Pressure Tank LOWES would work too...

    Roy Ken
  • Don't know why one outlet would do it and not others, but a small bladder tank will stop it, or a hammer arrester ???
  • Just get a water hammer arrester and put in the line the main water line. Had the same problem on my 5ver and that stopped the problem. Bought one off of Amazon that had shark bite fittings on both ends.....and cut the pex line in my storage compartment. Took about 5 minutes to install.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,211 PostsLatest Activity: Mar 08, 2025