Water pump on mains

[rallen]

Hello, our water pressure is quite low here and the water board have not really done anything about it in 10+ years now. To make matters worse I have a water softener which is not very large and it is causing a pressure drop on an already low pressure system. I was thinking of installing a water pump to help with the pressure. I have been to places in Europe where tall buildings or houses on a hill use their own water pumps to help carry the water to the top floors, so that is where I got the idea from.

I know however that here in the UK there are, or must be, regulations regarding fouling the water supply with dirty water and although I do not think a water pump in my house would foul the water supply, it may "suck" dirty water from neighbours's hopuses if the mains pressure is very low, or if there is a supply interruption somewhere. Just thinking aloud here, what are your opinions?

Thanks

 

[SimonG]

You can only pump 12 litres/minute from the mains.

How olds the property? Could be your pipe from the main causing the issue.

 

[AWheating]

you can get a directly fitted mains pump to a Max of 12ltrs per min from a few companies. If you want anything better you will need a break tank and pump set up.

 

[rallen]

Just so that I understand I can fit a mains pump as long as it is not more "powerful" than pulling 12ltrs/min. What happens if it is more or less poweful? Who would notice or what would the problem might be?

 

[rallen]

You can only pump 12 litres/minute from the mains.

How olds the property? Could be your pipe from the main causing the issue.

Hi, the house was built in the 1980s. The pipes coming in are 15mm internal diameter, 22mm external (plastic). But other houses around also have same low pressure issues, we are on a "hill" it seems...

 

[Mike Jackson]

Just so that I understand I can fit a mains pump as long as it is not more "powerful" than pulling 12ltrs/min. What happens if it is more or less poweful? Who would notice or what would the problem might be?

If you fit a larger pump it is likely that you will reduce the pressure to the surrounding properties who will then complain to the water undertaking. They will investigate and serve an enforcement notice on yo to remove the pump and may fine you. You will have wasted the money on the installation of the pump and risked a fine.

Worst case scenario you will draw contaminated water back into the cold main from a neighbour who doesn't have the correct backflow prevention fitted.

The water regulations are there to protect public health.

 

[rallen]

Got it, thanks. As a matter of curiosity, do I have a backflow valve fitted somewhere? The logical place to be would be the water meter itself, is this the case?

 

[Mike Jackson]

There will be a single check valve fitted at the water meter. You still need to apply point of use protection though.

 

[rallen]

Hi guys, I got a pressure gauge on the mains and measured 2.8-3.2 bar. So will this system benefit from a Stuart Turner pump which says adds 1.5 bar ? I cannot find what is the maximum output pressure from that pump. Thanks

 

[chris watkins]

So you haven't got low pressure after all, that is good, the legal min is 1.0 Bar (10Metre head). You must have poor water flow (the water softener is most likely taking out around 1 Bar dynamic) try putting the softener to by-pass to see if this improves the flow rate.
1.5 bar is the valve shut off pressure so this is the max it can deliver from a water supply at the same level as the pump but if you supply it with water at a pressure that has to be added on (less a small bit for friction), therefor is you 2.8bar & fitted the pump direct it would delver 2.8+1.5 = 4.3Bar however with this type of pump the flow would still be limited to 12 L/m or just about what a combi will deliver in hot water.

 

[cr0ft]

Isn't it easy enough to just replace the pipe from the stopcock in the street to the stopcock in the house with a bigger one? Unless you have a nice lock block drive or something running over the existing water supply pipe it would be a much better option in the longer term imo.

As others have said, pressure is not an issue, flow rate is the issue here so a larger water supply pipe should sort you out nicely.

 

[Ch4 plumbing]

Hi guys, I got a pressure gauge on the mains and measured 2.8-3.2 bar. So will this system benefit from a Stuart Turner pump which says adds 1.5 bar ? I cannot find what is the maximum output pressure from that pump. Thanks

As far as I know it won't add pressure but boost from below 1.5bar upto said pressure.
Just out of interest why do you need more pressure?

 

[cr0ft]

I think the op may be confusing pressure and flow rate perhaps. Don't know many domestic appliances that need more than 3 bars of pressure tbh.

 

[rallen]

The distance from the house to the water meter is in excess of 60 metres and somewhere underground, it sounds like a lot of work to fit new pipes.

The pressure of 3 bar was measured without the water softener.

Tomorrow I will measure the flowrate as well , litres per minute.

****

Why I need more pressure? Because I have another house in another place where the pressure is phenomenal and there we can really have multiple people using the water with no problems, showering, washing machines, flushing toilets, nothing is a problem. Just to explain the difference, over there we open the taps very gently, just as much as we need, over here its simply fully on or off and typically only one person at a time. It's like day and night between the two houses.

 

[chris watkins]

Why I need more pressure? Because I have another house in another place where the pressure is phenomenal and there we can really have multiple people using the water with no problems, showering, washing machines, flushing toilets, nothing is a problem. Just to explain the difference, over there we open the taps very gently, just as much as we need, over here its simply fully on or off and typically only one person at a time. It's like day and night between the two houses.

The reason your house here has lower pressure water supply (& flow rate) is that we in this country have had piped water supplies for some two hundred years & a lot of the supply system is more that 150+ years old, it leaks so much that we can only put the minimum amount of pressure on the system to deliver water to all the ends. Add to that, it was all sized to suit the population & pumping machinery available in those times & the system was design so that each user stored water on site (indirect systems) to overcome the peaks & troughs in demand.
No wonder then that if you want good flow rates & pressures you have to install your own break cistern & booster pump set.
Still drinking water for a couple of centuries to all parts of the country is not bad just as usual no plaining to start replacing them after the first 100 years!!!

 

[cr0ft]

I still think your issue is flow rate and not pressure. 3 bars of pressure is plenty, enough to run any shower or domestic appliance in the house.

If all of your cold outlets are mains fed which is often the case in older houses, do the following: -

Open the kitchen tap on full cold only. Measure flow rate in litres per minute.

Now open a second tap. Measure flow rate at kitchen tap. This will most likely drop. Whilst the kitchen tap is still running, go and measure flow rate at 2nd tap. Sum both flow rates.

Now open a 3rd tap. Keep doing this until the total flow rate doesn't go up any more. This is the maximum flow rate your water mains is delivering.

This will give you a good picture of where the flow rate limit is in your house, i.e. the water mains or internal plumbing. I suspect your flow rate, not pressure, is the problem and that this is due to the water mains. Raising pressure will do very little to improve this due to the fact that water is largely incompressible.

To give you an example, I was pressure testing around 20 litres or so of pipework yesterday. Once full, to take the pressure from 5 to 10 bars needed another 0.1L of water.

Let us know your flow rates and we can give you some better advice from there.

If the main water pipe is just hidden under earth and there are no driveways etc to dig up you could dig it out in a day with a digger. When comparing solutions you need to factor in that any pump or other mechanical solution will break down every so often. Shower pumps for instance don't tend to last much more than 3 years or so. Your new water mains would outlast you..

 

[cr0ft]

You can also buy an insulated box to bring the water mains into your home above the floor level, thus saving hassle having to break up your ground floor too if it's concrete. They cost around £50. MDPE pipe is cheap as chips and our water supplier round here does a new connection for free.

 

[Centralheatking]

I know Grundfos produce a 'wras legal' mains water suction pump set - dont know the ref no
but it is all ok to fit as it 'fits the regs' regarding flow rates. It is also quite cheap given the other
options you can consider.

This will suffice for a while until all your neighbours get low pressure and buy one for themselves
then you are all back to sq 1 !

Centralheatking

 

[PlumbersMate]

Hello, our water pressure is quite low here and the water board have not really done anything about it in 10+ years now. To make matters worse I have a water softener which is not very large and it is causing a pressure drop on an already low pressure system. I was thinking of installing a water pump to help with the pressure. I have been to places in Europe where tall buildings or houses on a hill use their own water pumps to help carry the water to the top floors, so that is where I got the idea from.

I know however that here in the UK there are, or must be, regulations regarding fouling the water supply with dirty water and although I do not think a water pump in my house would foul the water supply, it may "suck" dirty water from neighbours's hopuses if the mains pressure is very low, or if there is a supply interruption somewhere. Just thinking aloud here, what are your opinions?

Thanks

Had an email from Stuart Turner only last week about their new mains pump which removes the need for a breaker tank, they would be my first port of call

 

[rallen]

I ran some tests just now, so it is noon, I presume most neighbours are at work so I have all the pressure to myself. I bypassed the water softener.

*******************
Test 1: testing the taps which are nearest to the mains and low to the ground.

Mains pressure = 2.9 bar. With 1 tap fully open = 1 bar.

Flowrate = 1 tap = 15.3 lt / min. With another tap fully open = 11 lt /min (plus whatever the other tap was giving at the time, I presume equal)

********************************

Test 2: tests at the other side of the house in bathroom

Sink tap (15mm) = flowrate = 8.5 lt/min
Sink tap with bath tap open = 3 lt /min

**************************************

So this is what we experience in general in the house - the pressure is too low, and when someone is using the water then only the low to the ground taps and those nearest to the mains can produce some flow, all other parts of the house we get 3lt/min flowrate, impossible to take a shower or whatever.

**************************************************
Based on the above could someone please suggest the best pump to buy ? It seems there are many on the market but some require a "break tank" I was just told by Grundfos person - so will I actually benefit at all from the Stuart Turner mains pump?

 

[Sparkgap]

The much lower pressure with the tap open seems to indicate possibly restriction somewhere in the line or small incoming pipe (reduced bore through stop valve?). One site I look after used to have about 5-6Bar which we could use for pressure testing a boiler, now its dropped to just over 2 bar as the water board have lowered pressures around the place. Flow rate is not too bad but we have a pump in line to boost just in case. The flow rate didn't change much when we replaced the 1940s 1/2" supply pipe with 25mm poly, though it does run about 200m from the road.

 

[Mike Jackson]

Given that there is 15.3 litres/min at the kitchen sink a mains boost pump will make no difference as they can only boost to a maximum of 12 l/min. The difference in the bathroom will be down to internal restriction.

The only option to increase pressure and flow will be some kind of booster pump with a break tank.

 

[Centralheatking]

15 litres per min !!!! - there are families in Thames Water area that would chop their arm off for that performance - I am along side with Mike

If you really want to persue this plan then go ahead - it will be subject to water Regs and possibbly building regs if you ever want to sell your home - CHK

Given that there is 15.3 litres/min at the kitchen sink a mains boost pump will make no difference as they can only boost to a maximum of 12 l/min. The difference in the bathroom will be down to internal restriction.

The only option to increase pressure and flow will be some kind of booster pump with a break tank.

 

[cr0ft]

If you are seeing a large drop in pressure (dynamic pressure) from the static readings when you open just one tap then the limiting factor is the flow rate in from the water mains.

A moling company would run a new water mains for you with next to no disruption. You will pay a bit for the service but it saves digging and all the ongoing maintenance and servicing costs of any pumped solution.

I'm not a big lover of pumps for plumbing to be honest. They have their place but if you are keeping the property for the long term it's well worth finding the extra money up front.

 

[rallen]

So you are saying that the drop from 3bar to 1bar when I turn on one tap is because of my distance and quality of pipes to the water meter (about 60 meters away) ?