Local water supply

[Harry Bloomfield]

In a past life, I was quite involved in the water supply and drainage, but this puzzles me....

Our village is fed from a water tower, built on a hill. Every few months our normally good supply pressure drops for several hours, then comes back to normal - I'm just curious as to why this might happen?

Our electric shower still has enough pressure to work, but at a reduced flow rate. My best guess is that every so often, they deliberately allow the stored water in the tower to run down to ensure it is fully flushed so as to avoid Legionaires or similar. Anyone able to confirm that they do this sort of thing on a regular basis?

[Davey]

Have you asked the owner of the water tower?

[Chris Hogg]

Does the pressure drop affect the whole village, or just a few, and if the second, are they grouped in one location?

Our water supply is at the end of an old pipe, not up to current specs with respect to size etc and probably getting on for at least half a mile long. During the holiday season, the pressure dips dramatically, first thing in the morning and late in the afternoon, when all the holidaymakers are getting up and showering etc, and getting back in the evening to repeat their ablutions. Our old electric shower just wouldn't work on occasions, and at other times the pressure would drop very quickly, over a few seconds in some cases, meaning that you had to dodge out from the shower sharpish if you didn't want to be scalded. We have a pumped shower direct from the DHW tank now, to avoid the problem.

If you and your fellow sufferers are in a similar situation, maybe you're at the end of a long main, and at times someone, perhaps a farmer, draws off a lot of water and the pressure drops.

Alternatively, perhaps the water company just flushes the mains regularly.

[Clive Arthur]

It's a sticky ballcock in the tower.

Cheers

[Tim+]

Well whatever else it is, it won?t be legionella. That?s a problem for hot water systems as far as I?m aware.

Any major water users in your area? Farmers using irrigation maybe?

Tim

[Harry Bloomfield]

Tim+ formulated the question :

Lots of local farmers, but all seem to have their own sources - streams and ponds.

To reply to the other suggestions...

It is mostly a static local population and the supply pressure is always good apart from these rare pressure drops. I cannot see it being a sticking ballcock - we are at a high spot for several miles around, so water will need to be pumped up to the tower, so the pumps will be started and stopped on water level. When they flush the mains, they write to us to warn us in advance.

It is as if there are two pumps and one gets turned off, or trips out sometimes.

[Brian Gaff]

Don't know I'd have hoped they actually cleaned it as well. Could there be a leak somewhere that is only noticed when the water table is low? Brian

[David]

Just wondering about the difference in height between the top and bottom of the water tower, and the bottom of the water tower and your property.

If you are more or less level with the water tower then a difference in water level might make a difference, but if you were, say, 100 feet lower than the tower I would have thought any difference would make very little difference.

Cheers

Dave R

[Harry Bloomfield]

David presented the following explanation :

The tank section of the tower is around 20 feet high, the base of the tower is (wild guess) around 70 feet higher than our house. So lowering the level to the bottom of the tank will make little difference to pressure, however if the water were fed into the tank at a slower rate that probably would, but thinking about it air would probably be drawn in and appear from our taps.

[Mike]

We used to have a sever drop in pressure on Saturdays, I don't know why but I managed to get the local water company to put a data logger on our supply and after that they did something, presumably to their control gear, and it is nowhere near as bad as it was, although still noticeable sometimes.

- Mike