smell from one tap. How can this happen?

[deanomc]

people, this is driving me bonkers !

I have a crosswater pro3000 thermostatic 3 way mixer value in my bathroom. If I fill the bath using either the fixed shower head or hand shower then the water has no odor. However, If I fill the bath using the bath tap, the water sometimes, not always, has an extremely strong smell of sulphur/earth. How can this be if the valve is using the same water input and the bath tap is only approx 1m away from the valve.

Incidentally all other water in the house seems perfectly normal. I have drawn out the layout to the pipes in the house in the hope that someone can solve this. Yes, as you can see from my technical drawing I'm no plumber.

I have done the water test where I have filled two cups, one filled with the bath tap and one filled with the shower head and removed them away from the bathroom and still the bath tap one smells therefore the contamination is definitely in the water and not in the bathroom. There are no dead legs in the pipework.

Thanks

Boiler is a Valliant ecotec32.

 

[Chuck]

the valve is using the same water input and the bath tap is only approx 1m away from the valve.

Some sort of biofilm contamination in the 1m length of pipe leading to the tap or in the tap itself, perhaps? Do you use the bath tap less frequently than the shower?

When you say 'tap' do you mean there is a valve at the bath end of the 1m pipe or or is the valve on the three-way mixer and the 'tap' on your diagram is just an outlet. (I assume the latter.) If so, are the gradients such that the 1m pipe remains full of stagnant water that is gently warmed each time someone has a shower?

 

[deanomc]

Some sort of biofilm contamination in the 1m length of pipe leading to the tap or in the tap itself, perhaps? Do you use the bath tap less frequently than the shower?

When you say 'tap' do you mean there is a valve at the bath end of the 1m pipe or or is the valve on the three-way mixer and the 'tap' on your diagram is just an outlet. (I assume the latter.) If so, are the gradients such that the 1m pipe remains full of stagnant water that is gently warmed each time someone has a shower?

Chuck

The shower gets used twice a day, the bath usually once a day.

The valve is in the three way mixer so the tap is just an outlet. As for the pipe gradient, possibly an issue as I can't tell as it is tiled in unfortunately. If there is a contamination in the pipe or tap can there be enough in a 1m length to produce such a strong smell. A small cup taken from a full bath has a strong smell.

 

[Chuck]

If there is a contamination in the pipe or tap can there be enough in a 1m length to produce such a strong smell. A small cup taken from a full bath has a strong smell.

If what you are smelling is hydrogen sulphide (rotten eggs), which usually comes from biological contaminants reducing the sulphate in the water then you don't need much for it to be very smelly.

Have you eliminated some chemical reaction involving the bath tub by taking a sample directly from the tap?

You could get a sample of water from you bath tap tested to see what's in it. You'll need two samples the other from the kitchen tap to compare. If you google 'independent water testing' and include your town/county in the search you'll probably find a couple of local firms. Tell them the problem and ask whether they can help. If they can, they'll tell you what type of analysis is needed and provide sample bottles and instructions how to collect the sample. Expect their advice to cost about £50-£100 and there's always a possibility that what they tell you won't give a definitive cause, so I'd only try this as a last resort.

 

[Rob Foster]

I would turn the water off to the house, then open the bath tap and the shower let water go . Then fill a squeeze bottle full of something really quite nasty, squirt it back up the open tap end leave it fir a while , or you arrange a pop bottle with same stuff in connect to open tap and let it soak , then turn water back on and flush nasty chemicals out ..Rob Foster aka centralheatking

 

[deanomc]

I would turn the water off to the house, then open the bath tap and the shower let water go . Then fill a squeeze bottle full of something really quite nasty, squirt it back up the open tap end leave it fir a while , or you arrange a pop bottle with same stuff in connect to open tap and let it soak , then turn water back on and flush nasty chemicals out ..Rob Foster aka centralheatking

Can you recommend a p[product nasty enough?

 

[deanomc]

If what you are smelling is hydrogen sulphide (rotten eggs), which usually comes from biological contaminants reducing the sulphate in the water then you don't need much for it to be very smelly.

Have you eliminated some chemical reaction involving the bath tub by taking a sample directly from the tap?

You could get a sample of water from you bath tap tested to see what's in it. You'll need two samples the other from the kitchen tap to compare. If you google 'independent water testing' and include your town/county in the search you'll probably find a couple of local firms. Tell them the problem and ask whether they can help. If they can, they'll tell you what type of analysis is needed and provide sample bottles and instructions how to collect the sample. Expect their advice to cost about £50-£100 and there's always a possibility that what they tell you won't give a definitive cause, so I'd only try this as a last resort.

Thanks again. Do you know if any of the water testing kits will suffice or are they useless.

 

[Rob Foster]

Can you recommend a p[product nasty enough?

Bleach, mr muscle that kind of stuff cillit bang, pub beer line cleaner is ace fir most purposes
It’s a bit cavalier but that’s what I would do, maybe open a window

 

[Chuck]

Thanks again. Do you know if any of the water testing kits will suffice or are they useless.

Depends what they test for. The 'comprehensive' ones are as expensive as getting a local lab to do the test for you.

I'd try Rob Foster's suggestion first. Mine is more of a last resort and it may only tell you that you need to start replacing pipework and the advice will cost you a £100 to add insult to injury!

 

[PETE 123]

maybe flux in that part when made or installed

 

[deanomc]

maybe flux in that part when made or installed

I thought that initially but the bathroom has been installed for a good few years. Can the smell of flu still be strong after such a long time.

 

[Wirdy]

I've used hydrogen peroxide for cleaning slimy pipework with good results. Needs to sit for a couple of hrs though.