DIY Doctor UK DIY Forums

Hi,

I'm not a plumber as will be easily evident but have to do the best job I can in resolving my issue so please answer based on that. I am not earning due to pandemic and stuck for cash to bring someone in.

Situation I have is that we have a mains stopcock outside front door. A stopcock in kitchen, a large cold water tank and small black plastic expansion overflow water tank in loft.

I had always believed each cold tap was fed directly but apparently not based on reading this morning. Due to our cold water storage tank in loft not having a lid, not one fitted properly anyway, I have now become a little concerned. We had a rat in loft some time ago and found it dead in the loft but obviously lofts can house all sorts. The tank itself is not particularly easy to get to being someway down under rafters toward the eaves.

I'm looking into changing cold water tank to get one with a lid.

I need to check one thing first though and if there is a danger to drinking water supply I will change tank. If not, I will wait until 2021 when I plan on changing from back boiler to combi and getting shot of tank in loft altogether.

Issue:
I was most concerned to find out if the kitchen sink cold tap is the only one on the mains. I turned main stopcock off outside front door. Ran taps at upstairs sink, downstairs kitchen and bathroom sink taps. I forgot to try the bath taps themselves but can do so again if needed based on answer. We have a bathroom(sink, toilet, bath, electric shower), Shower room (sink, toilet, electric shower), kitchen sink and outside tap. Sorry for long post but want to give as much info as possible rather than to place obstacles in your way to answer me.

I never tried our showers as they are electric showers and I presume that if I tried turning those on without water supply; if it happened to be on mains; that it would either not work at all or worse potentially destroy the shower as no water going over elements; though I suppose I could try the showers on cold only which would likely be safe?

So, I only turned off mains stopcock outside, not the one on pipework under sink in kitchen (difficult access). Ran cold taps in upstairs toilet, downstairs bathroom sink and kitchen cold tap. All these cold taps stopped completely though downstairs bathroom sink tap did so after a bit of spluttering and increasing decreasing flow. But they did all stop. So no cold water left running anywhere. The only mixer tap is in kitchen.

I never flushed either of our toilets and the only tap beyond the bathroom is an outside tap.

Hot water was still available in all locations. So at this point there were no running cold taps and I turned the hots off. But the kitchen being a mixer I simply moved back to cold position and it kept on running. I gave it the benefit of the doubt but it kept running. At no point on moving from hot to cold position did it run as fast as hot position but I'm concerned that it simply didn't stop.

Does anyone know what could cause the kitchen tap to do this. My main, though it may seem to you a daft worry, is that through some reason, even siphoning from hot somehow, is could the mixer tap at kitchen sink be getting water, even minimal but still potentially contaminated water from cold water storage tank.

I have no idea and can't find the answer elsewhere. I want to feel assured that I am not wrongly assuming the water at kitchen cold tap is solely from mains and therefore safe. Can our plumbing account for the cold water tank pushing water to that tap somehow?

I really don't want us drinking anything from our uncovered cold water storage tank in loft. But due to finances and likelihood of changing to combi next year and getting shot of tanks altogether don't want to waste money when I simply haven't got it. This is solely a 'safe drinking water' issue and all else I'm happy enough with until next year.

Lastly, the reason the lid doesn't fit is whoever put this in ran overflow pipe over lip of tank and the copper pipe is preventing the lid going down onto tank. I assume he should have put a hole in lid to allow for this. I'm not looking forward to this job but I can do it. I've changed taps and installed toilets before so I think I'd be okay but it's the knowledge on this issue I need to know which tack I need to take. If I can get away with not changing the tank at this point and to minimise work but to also give the tank a cover could I double up a high gauge double layer of DPC to simply stop contamination for the time being.

Any advice welcomed. Sorry to add this.
I'm sorry and do understand you are all plumbers and I appreciate the job you do is skilled. But please, there's no need to answer if you just want to add a 'get a plumber in' remark. You can use the remark if you also want to add something to the question but please not just the 'get a plumber' remark. Its all over the internet and outside of 'dangerous things' is unnecessary. I will weigh everything up and determine the potential for me to mess up before doing it anyway. This isn't gas work so I just need advice please on whether my drinking water is safe.

I've been drinking the stuff for years and knowing the kitchen cold tap water is safe is enough for me for now. If all cold taps sound safe to you then that is a bonus.

Thank you all.

Hi dulede
You are probably worrying unnecessarily.
It is likely that cold mains will be fed to your kitchen tap, electric showers outside tap and tanks in loft.
Try turning off the mains again - make sure you have turned it off completely by turning on the outside tap - it may run for a short while as the water in your pipes empties.
Do not be concerned about your showers they will sense zero water pressure and will not turn on. You can now check your kitchen taps and see if there is any cold mains feed. You should be able to visually tell the difference between mains and tank fed supply. If you still have mains in the kitchen there may be two mains into your house.
Regards S

Hi Stoneyboy

I am probably worrying for nothing. I suspect; quite confidently; that the cold taps, the ones that really matter, are all being fed from mains. Regardless of what happened when I moved from HOT to COLD position on kitchen mixer tap the fact was it initially stopped dead when set to cold position. Same for upstairs shower room sink tap and bathroom sink tap. Seeing I don't expect to be drinking from bath taps that is no issue either.

It is better to have asked as it does give extra reassurance. I have a particular concern over mice and rats as for some reason, as my home is a terraced house, they have always managed to get into loft space no matter what I've tried. Fact is unless you tear your home apart and crawling down to within inches of roof eaves they are always going to be able to get in if they wish. The local football ground was knocked down many years ago and the belief is that the area all around that had a mass of rodents that needed homes and they just repeatedly return once cold weather threatens. Disgusting but nigh on impossible to completely avoid. I've tried rat mesh and pest control. Can do no more. One of those filthy buggers ending up dropping into the water tank is a horrible idea.

I'll wait and get gas CH changed to combi next year and that will mean water all on mains then so bob's your uncle. Once again thank you for your answer.

Hi dulede
If your tank lid is a reasonable fit apart from near the expansion pipe, just cut a slot for the pipe so the lid sits down. Do not be tempted to use poison in your loft - it makes rodents thirsty and keen to get into your water tanks.
If you go for a combi make sure you have at least a 25mm mdpe pipe from the mains into your house. Bear in mind that you will be dependent on mains water pressure and if you live in a densely populated area there will be times when everyone is using water and your system will not work well.
Regards S

Hi Stoneyboy

I will do the slit and sort the lid out that way. Just use gorilla tape to bring it back into shape if necessary. I can't take a risk with poison in case it took it and managed to get into living space somehow....have 2 cats. If I had my way, I haven't as married, I'd break into ceilings at each point between joists and cement or mesh up any potential space where rodents can come from one building to another and then make good or get my brother to re-plaster. Even then though, our house is built in 1880s and dealing retrospectively is so much more hassle than building 'defences' into a new build. I think but can hardly be sure that rats get into the cavity at some point and then can come up within the roof structure at either first floor flat or second floor pitched roof level. Pretty much screwed as I had hoped to prevent with rat mesh behind gutters but that never worked. Every year we get them or it return as it goes from summer/autumn into winter. Disgusting.
Many thanks again.