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How to fix water hammer after change of meter?

goatie

I had a change of water meter and now have water hammer in my house I ran all the taps including the washing machine taps hot and cold. I did this a couple of times but it remains on my bathroom sink mixer tap. I have never had water hammer before. I have not run the washing machine it was there too. I have new little taps in the cupboard under the bathroom sink should I alter them?

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goatie

just to add with the outdoor tap closest to the meter you cannot hear water hammer unless you attach a hose then you can hear minor water hammer going into the house. Is it another faulty water meter?

JacobZ

Hi @goatie,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Water hammer is usually caused by water flow stopping suddenly, which creates a pressure shock through the pipework. It can become noticeable after a meter change, particularly if air has entered the system or the water pressure has changed.

As a homeowner, the main thing you can safely try is bleeding the lines by turning off the water supply at your meter, opening all of the taps throughout the house, then turning the supply back on slowly and allowing the taps to run until the air has cleared and sputtering stops. You need to ensure every available tap is run at the same time to ensure air gets cleared.

Unfortunately, if this doesn't prove useful, the next step would be to have a licensed plumber assess the system. They can check the meter installation, household water pressure, the basin mixer and isolation valves, and determine whether an arrestor, pressure-limiting valve or another adjustment is required.

Given the problem started immediately after the meter was replaced, it would also be worth contacting the water provider or installer to let them know.

Let me know if you have any further questions.

Jacob

goatie

what about the toilet and evaporative air conditioner

EricL

Hello @goatie

Yes, both of those need to be included in the purge, this is of course on the condition that the evaporative air conditioner has its own tap.

If you need further assistance, please let us know.

Eric

goatie

how do I purge an evaporative air conditioner tap? I take it I just flush a toilet.

goatie

I should add we have already run all the taps but we did not switch of the water first

JacobZ

Hi @goatie,

If you've already run the taps and it had no effect, it can't really hurt to try again before contacting a plumber as long as all your taps have a safe drainage point.

Upon further reading, I'd change the approach a little bit to what i previously described. There's no real need to turn the meter off and then have them all open before turning it back on. Instead, I'd suggest you turn the meter off and on, just as a starting measure, then progressively open the taps, starting with those closest to the meter, and working away and upwards. If you imagine the meter is the starting point for all the pipes, the goal is to have water flow from the meter through every single pipe it possibly can to push any air out.

Purging the evaporative cooler would really depend on the system. They often have an isolation valve that needs to be turned on to allow water into the system, as well as a drainage tap, which sometimes looks like a garden tap. If you aren't sure, it might be worth contacting an air conditioning specialist for their assistance.

Purging the toilet would just mean flushing it a few times.

Make sure you run the taps for a minute or so, and if the hammer becomes more pronounced or concerning, turn the water meter off and contact a plumber.

Hopefully this should help.

Jacob

goatie

hi I had the evaporative air conditioner guy out he put an arrestor on the air conditioner unit. He switched off the water and then switched it back on and ran the unit, I then ran all the cold water taps. The water hammer stayed. I ran all the cold and hot water taps today except the evaporative and flushed the toilet. I did this twice. Starting from lowest to highest, ie front of the house but then the bathroom then went to the front of house kitchen then back toward the bathroom again laundry. Nothing helps. I have had the laundry, cold water and hot water taps changed. When the hot water tap was changed the water hammer almost disappeared in it entirety except for a minor amount on the hot water tap but came back when I ran the air conditioner. Today I found out when I attached the hose to the front garden tap and switched the water of and on I heard mild water hammer which makes me think it’s the water meter again.

JacobZ

Hi @goatie,

If that's the case, then I'd contact your local water authority and have them send someone out to inspect. If the water meter is the issue, then they would need to assist.

Jacob

goatie

if it’s not the water meter is there anything else I can do?

goatie

I just altered the newish isolation taps under my bathroom sink and the water hammer is gone on the cold water but not entirely on the hot water tap. The water aerator was taken out of the mixer tap meaning that it flows faster and gives me hotter water if I put that back in will it help.

EricL

Hello @goatie

I suggest asking your plumber if a water hammer arrestor will help in alleviating the symptoms in your plumbing set up. Please note that the arrestor must be installed by a plumber as it is regarded as regulated plumbing.

In regard to the aerator, it's best to put it back if it was originally installed on your tap. But I'm not sure if it will help with your water hammer issue. I recommend speaking to your plumber about it.

If you need further assitance, please let us know.

Eric

JacobZ

Hi @goatie,

Unless you are a plumber, then there's not a lot you can do outside of trying to purge the lines of air.

An aerator on the tip of your tap is unlikely to have any real effect.

Unfortunately, at this point, we can't really assist you any further. You are going to have to either contact a plumber or your local water authority for assistance.

Jacob

goatie

I have arrestors on all my taps now.

goatie

hi I forgot to ask to purge the air why are you suggesting turning the water meter off and on before opening the taps surely that would put more air in the pipes?

JacobZ

Hi @goatie,

It was just a good starting position and isn't really essential. Turning the water meter on and off isn't going to put more air in the pipes.

If you are still having trouble, I'd suggest you contact a plumber.

Jacob

goatie

can an outdoor tap give your home water hammer ie if the valve is gone

EricL

Hello @goatie

I'm not sure if the outdoor tap will create a water hammering effect in your home if it has no valve. These are queries you'll definitely need to ask your plumber. They will be able to investigate your plumbing system and figure out why you have water hammer occurring in your pipework.

Eric