Old loft water tanks and legionella testing

[Leonard V]

Hi,
We have a few loft water tanks on our estate that have lost their purpose due to flats switching to combi boilers.
The plumber who advised us says that he will have to test the stagnant water for legionella before emptying/removing them.
Wouldn't a bottle of bleach, or so, poured into the tank resolve the potential bacterial contamination?
Thanks!

 

[muggles]

Probably, but you'd still need to test that it's worked

 

[denso13]

Wouldn't a bottle of bleach, or so, poured into the tank resolve the potential bacterial contamination?

I'd think so but why bother if the cisterns are being removed? Are you saying they are disconnected but still have water in them?

 

[Leonard V]

Yes, that's right.

 

[Mottie]

Probably been used as toilets by plumbers caught short in the loft......

 

[Madrab]

They will be large cisterns if they are tenements.

I'd ask the plumber how he would be treating the water if they were found to be positive for legionella and he can just use that by default before draining. It would either be chlorine or ammonia.

Would need to be careful what concentration of either is going down the drains.