Bath tap running slow

[Chris R]

I am getting only a miserable trickle of cold water from our bath tap. The bathroom was new about 8 years ago so all the plumbing is modern. Our mains water pressure is high and all the other taps & WC in the bathroom have a very healthy flow of cold water. The hot water is gravity-fed and a bit slow but acceptable - the bathroom is a long way from the loft tank. All cold taps in the house run at mains pressure. I don't know how the pipes run but I can't imagine that the bath tap has its own pipe run - it must be teed off the same supply as the other taps in the room. The tap is a shower mixer tap. The cold feed to the spray is equally poor. I guess suspicion has to be on the tap itself, but is there anything else I should try?

[Woody]

Check that. Your bath cold tap should be fed from the cold header tank from the cold mains.

Do you live in a hard water area? It could be that the taps - and possibly the stop-c*ck feeding from the header tank - are furred up.

[Java Jive]

I'm afraid this is probably another example of modern 'design' being victorious over functionality. In my 80s house, I have cold-taps like that in the bathroom, whereas the sink one runs too powerfully off the mains.

'Traditional' (that is: invented by the Victorians, so they tended to work well rather than look 'cool') tap designs took flat washers, and had the great advantages of

1) Being easy to replace 2) By and large tending to give a steadily increasing flow as you open up the tap, making them suitable for use in a wide variety of situations such as dribbling over vegetables and salads as you wash them, mixer taps with a shower attachment, whether one built into the mixer tap or plugged onto the taps, etc, etc.

However modern taps seem to have been designed primarily to look 'cool', but also to turn on all at once. There are several bad things about this:

1) Coupled with modern basin design, and high water pressuire, the result is a wet crutch, and looking as if you've pissed yourself. 2) They're hopeless for mixer taps, trying to get a steady dribble for washing vegetables, etc. 3) The internal design usually has a throat with a roughly conical rubber 'washer' that plunges into the throat to stop the flow, but, as you've discovered, after a while on the cold taps the rubber gets inflexible, and tends to stick in the throat instead of rising out of it to allow the flow. 4) They're a pa> I am getting only a miserable trickle of cold water from our bath tap. ...

[Chris R]

Our mains water pressure is high and all the other taps

Really? Why is that? You may be right but it would have meant running a very long supply pipe from the header tank just to feed this one tap (and I suppose the lavatory cistern?).

Thanks for the reply. We are not in a hard water area.

[Brian Gaff]

Well I'd have thought all taps in the bathroom would have been from the header tank. The last time this happened to me was when some air, goodness knows from where, got into the long run from the cold tape on the basin, to the bath/shower. It meant blasting mains water up the bath end to clear it. To this day I have no idea where the air came from as there were no leaks.

Brian

[Java Jive]

Probably, the air was originally dissolved in the water and something in the pipe work made it come out of solution.

A few years ago, I was walking up my road to the shops, and there was water flowing everywhere. Gingerly avoiding the puddles, my initial assumption was that there was a leak, but looking up the road it was clear that the water was deliberately being allowed to run to waste by water company staff. As I drew level with them, I asked what was going on, and they said that somehow the water being fed to the area had too much air dissolved in it, and was causing problems, so they were trying to clear out the mains.

I should've st> Well I'd have thought all taps in the bathroom would have been from the

[Java Jive]

Meant to add that you could try swapping the washers on the hot and cold taps, just to see what happens over the next few weeks. If the problem repeats itself, then my diagnosis is correct, and you're either going to have resign yourself to living with the problem, as I do, changing the washers every few months, or replacing the taps with ones that have a better internal design.

H>

[Woody]

The taps should always both be supplied from a header tank, albeit the hot tap via the hot tank! There can be one or two tanks so long as they are both at the same height. They don't necessarily need to be the same size but it is a good idea if they are. This is to ensure equal feed pressure. Did you not say you have a mixer-tap shower (Mira?)? If so then it would not work if the cold water were at mains pressure, however an electric shower is specifically designed to be supplied at mains pressure.

The length of the feed pipe from the tank to the tap (or any difference between cold and hot) is of no consequence provided there is sufficient head. The bottom of the tank should ideally be not less than 1m above the highest position of the shower head or the tap, whichever is the higher.

ALL other taps in the bathroom - i.e. the washbasin - and on any other cold outlets in the house should be fed from the rising main. Because the bath tap water comes from a potentially stagnant source it is generally not a good idea to drink water from the bath taps. If a common tank is used to feed both the cold bath tap and the hot water cylinder it is an even worse idea to drink cold water from the bath tap as the expansion from the hot water system overflows into that same cold header tank!

[Scott]

Does this only apply if you are using a shower or mixer tap? If there are two separate taps, I can't see what difference the pressure makes.

Is this common practice? I was always told not to drink the water from the bathroom because it would normally come from the roof tank.

[puffernutter]

I thought the rule was (and I could be wrong - I frequently am, just ask the wife :-) was that the kitchen tap MUST be fed of the rising main, anything else was up to the discretion of the builder.

We have a Victorian terrace (1890) and we have the kitchen taps, utility room sink taps, downstairs cloakroom toilet and taps and upstairs toilet and basin taps off the mains with the bathroom (bath cold and hot taps, sink taps and shower (pumped Triton) off the header tank.

Cheers

Peter

[Brian Gaff]

Ah, the old wrong type of water problem obviously. I tell you what a few days ago I was running the mains water and the smell of chlorine was awful. I decided not to actually drink it for a while. Brian

[Chris R]

Not a proper shower, just a shower head off the mixer tap. It has never had enough flow to allow it to be used as a shower.

There is a separate shower but that has its own separate pumped supply. Ideally we would have fed the bath off that as well - as it is, it takes so long to fill we tend not to use it.

[Andy Champ]

I suggest you turn your main stopcock off a bit. That should cut down the flow rate.

My son's place had "traditional" taps. One day the thread failed on the cold tap, and the tap jammed full on. It was mains fed.

The basin overflowed. The flood severely damaged the lounge ceiling, and flooded the shop on the ground floor. We now know _exactly_ which kitchen cupboard has the stopcock hidden in it. Which came in handy when the feed pipe to the new cistern popped off a couple of months later!

Andy

[MCGARRY]

Not a simple solution to the problem, but why can't the british make mains pressure immersion heaters. It solves this problem of getting warm water at th eright temperature and makes th eplumbing system simpler. I've never seen a header tank system in France, and never heard of a mains pressure imersion heater blowing up.

[MuddyMike]

They are freely available just not very popular for some strange reason.

Mike

[Andrew Gabriel]

All low pressure taps will come from the same tank in the loft. The other (smaller) tank is for the primary boiler circuit and central heating, and contains inhibitor and/or black sludge.

... which is the correct answer. However, if you have thermostatic mixer outlets, unless they were designed for mixed pressure operation (expensive), then they will require feeding from the same source.

[Andrew Gabriel]

We do.

France allows tanks which continuously dribble as they reheat and the water expands. Dribbling tanks are not permitted in the UK, requiring a more complex air expansion space to be maintained.

[McGyver]

The culprit is almost surely in the faucet. If you remove the cold water faucet and then have your assistant turn the house water back on all the way and then immediately off while you watch the water entering the bath, you will have narrowed down the possibilities. If the water come in with full pressure, like a garden hose, the problem is in the faucet. If the water comes out in a miserable trickle, that leaves you with a problem in the pipe.

Assuming (going with the odds) that the faucet is the problem, try replacing the washer first. If that doesn't help, replace the faucet.

McGyver