Mains Water Pressure Halved - Water Board says no change?

[robt100]

Hoping someone might have some ideas on this one. Apolgies for the long first post!

Moved into our house in May this year, water pressure has been good since we moved in (And also when checked at viewings 3-6months beforehand). But in the last 3 weeks the mains pressure has dropped out to half what it was. I have an RO system for work which needs a minimum of 55psi to work correctly, previously the pressure was hitting around 65psi with the normal gate valve opening on the RO. Now it just about gets pasi 30psi. It is also noticeable in the house, especially if two taps are on at once etc.

Had anglian water out today to check, says no leaks on the mains. He also said no leak on the pipe to the property (though not sure how he can check this in a row of 3 houses feeding off the same street mains feed as surely someone may have been using somehting). He tested the pressure at the street mains as 3.5bar/50psi static and 3 bar/43psi dynamic with a flow of 25lpm. Says thats the same as someone else had measured back in May at a suspected leak. So how come at that same time in May I was getting 65psi? On asking him the question he pretty much made his excuses and left, probably on account of not wanting to stand around in the rain for much longer...

I know the readings are technically within spec, but I wondered if anyone had any suggestions on any further investigation I could do to try to find the issue? As it is effecting my work (I need a supply of purified water from the RO). At first I did wonder if the shared feed from the 3 properties might have an issue, but the pressure drop is constant, whether I try the RO in the morning, evening or past midnight, and didnt happen for the last 5 months.

One thing I did notice when I had the higher pressure, is every now and again there was a split second 'hiccup' where the pressure gauge would drop 10psi then back again, almost like letting a bubble through the system or a vacuum releasing. It isn't an issue with the stopcocks either, either internal or on the meter as the issue is on both a metred internal and unmetred external feed to the property. I was also told the water here is gravity fed rather than pumped, so no problem from that side of things.

Any ideas would be much appreciated!

 

[Madrab]

If he has qualified the mains static and dynamic and mains pressure (with a mains they are usually the same thing as a district main is always usually under demand though it may be the dynamic pressure on the supply pipe to your property) then it has to be downstream of where he took the reading where the pressure is being restricted. I presume a RO, is a reverse osmosis system?

I think you need to obtain a pressure gauge and start testing static and dynamic pressure at various points to see where the drop may be occurring. First one at the mains directly after the stop tap to confirm his readings.

 

[robt100]

Yes RO is reverse osmosis system. Checking after he left with the valve fully shut it is getting about 2bar. Still not sure how he can measure 3-3.5 at the Supply pipe, yet I WAS getting 4 bar at the house???

I have a relative who was ex-anglian water who still has his pressure tester, so may need to grab this when I see them next. As an aside, when the readings were taken and he said there was no leak between the location of the reading and the house, how on earth is he working that one out? Surely all 3 houses couldn't have had nothing running all at once? Got a feeling maybe he was just trying to fob me off?

 

[Madrab]

I always advise clients to check and test their own mains before calling in the transporter so they have a starting set or readings and then when they do arrive make sure there's plenty of tea and biscuits onside to get them onside (plain not choccy or course, don't want to spoil them). There will always be shysters that will say anything to try and prove they did what they were supposed to so the trick is to be clever. If you rock up with tea and biccys that gives a great reason to 'hang about' and get to see what they are doing, subtly or course

 

[robt100]

Pressure on the line to the outside tap I had measured as dropped (from 65-70psi down to 30-35psi), inside no measurement but quite obviously lower pressure than before. Both taps come in on different lines, well, the outside tap doesnt seem to run through the meter anyway and he mentioned two stopcocks/taps in the road, so I assume one is the 2nd supply line to everyones outbuildings.

Offered tea, coffee and biscuits on arrival, but they were rejected to be fair it was one guy by himself and the rain was at a 45 degree angle, reckon he just wanted to get back in the van ASAP.

Any suggestions for points to measure from between my feed and the street feed? As im on the end of a line of 3 fed from the road, so going to have to get very friendly with the new neighbours to check pressure drops between there and here. Though as both feeds (on seperate pipes) have dropped, it makes me think it was on the street feed, but as its within tollerance of what they legally have to supply they will just shrug their shoulders at it.

He seemed to suggest the pressure can't drop because its not pumped from source....im guessing he has never heard of valves and pressure reducers?

 

[Madrab]

Fair play to him then if the weather was bad so he gets the benefit of the doubt.

Yes, the issue is that as long as they deliver the minimum then there isn't a lot you can do. If there has been a lot of other user coming on line on your specific district main ( new housing developments, construction, industrial areas etc) then yes, that's always a possibility that the available head is reduced.

No real suggestions on how to test between your stop tap and the transporters external toby, as you suggest, get the neighbours onside, or dig down and tap the supply pipe, which would really be a sledgehammer to crack a nut.

 

[fixitflav]

the pressure can't drop because its not pumped from source....im guessing he has never heard of valves and pressure reducers?

Maybe there's a pressure controller and AW have lowered its setting to reduce leakage. Whether they'd admit it is another matter.

 

[robt100]

Maybe there's a pressure controller and AW have lowered its setting to reduce leakage. Whether they'd admit it is another matter.

Got a feeling that may be the case. As I spoke to a neighbour who is off the same road supply but different line to the property (if that makes sense? So a detached neighbour) and they also said their pressure seems to have dropped the last few weeks. Shame its still within spec and I can't invoice them for the cost of a booster pump and the electric to run it. One of the selling points of getting the house was the decent water pressure

 

[fixitflav]

Got a feeling that may be the case. As I spoke to a neighbour who is off the same road supply but different line to the property (if that makes sense? So a detached neighbour) and they also said their pressure seems to have dropped the last few weeks. Shame its still within spec and I can't invoice them for the cost of a booster pump and the electric to run it. One of the selling points of getting the house was the decent water pressure

If you did use a booster pump the regs might say you need a break tank, not draw direct from the mains, so you lose the 2 bar advantage.