Regular momentary dips in mains water pressure every 15sec

[deFoix]

Hi all, hoping for some help here.

Over the last 2 months I've been experiencing dips in water pressure from my kitchen tap. The weird this is that these are momentary dips in pressure that occur every 15 seconds. It seems to happen in the mornings and evenings and is making my plastic pipes to my water softener clunk. I've checked round my flat and I can't see anything that is causing a issue.

Given the regular interval of the dip in pressure I'm thinking it's a Thames Water issue on the street? Does anyone have any ideas?

Thanks.

 

[snowhead]

How many flats are in the complex with yours?

Quite often the water supply is pumped withing a flat complex, it may be an internal Building management / Landlord issue to resolve.
The pump(s) / storage system could be at fault causing a pressure drop at peak times.
Kitchen taps would normally be direct from the incoming water supply, but the pumped side could still be causing the pressure drop.

 

[deFoix]

Hi Snowhead,

Its the top floor flat of a converted victorian townhouse (4 flats total) so there's no internal pumping arrangement. I need to go down to my neighbors and see if they are having the same problem. The fact it's every 15 sec pulse drop in pressure makes me think there is some value being actuated somewhere in the street. I called Thames water but they say nothing is going on in the area.

 

[deFoix]

Hi everyone. Ok, so this issue is still occurring. I'm in a Victorian house converted into 4 flats in SE London. I've checked with the other flats and we are all experiencing the same intermittent short, sharp, dips in pressure (every 15 seconds - like clockwork), but it's only on certain days and at certain times. Surely the only thing that can cause a sudden dip in pressure is a value closing? Are there any Thames Water engineers on here who can advise? Thanks.

 

[Ben-gee]

Possibly a neighbouring property has a mains boost pump, this could be robbing you of pressure.

They should not be allowed, but for some reason they are approved now?

 

[Last Plumber]

I would tend to think along the same lines as @Ben-gee. Possibly a residential building pulling off the mains or even commercial/industrial premises? Have you asked Thames Water to test the mains to the property you are in?
I can't speak for London but in the North, they will come out to test the mains if you report an issue like this, particularly if you report a low pressure problem. If they witness it, they 'may' feel compelled to investigate further. You never know your luck!

 

[PETE 123]

Could be a boiler safety valve discharging after its built up pressure filling loop turned on or letting by.
[automerge]1598513416[/automerge]
Try turning electrics off then try water to water softnener.

 

[deFoix]

Thanks for the suggestions. I've had some correspondence with Thames water but since it's only causing very short dips in pressure intermittently they're not bothered to send someone to investigate. I was thinking also maybe a hydraulic ram pump off the mains would cause the dips but not sure if these types of thing are in use. An electric pump wouldn't cause regular short dips in pressure every 15 seconds.

 

[q11]

Our whole street's supply is boosted by a permanent pump. The water company installed it many years back to 'ensure steady supply at good pressure'. A failing pump (or it's power supply) might produce such regular 'hiccups', possibly only noticed / triggered at hours of peak demand?

You would hope their fault team have access to such info about your street, but you never know.