I have an site that both an insurance company and builder have requested a RA for re a water leak before work will commence. In effect the leak was caused by a waste connection from a toilet that has allowed waste water from both a sink and a toilet to enter the 'screed' within a house. Has anyone come across this before? and if so, is there any evidence of a possible bacterial contamination to anyone involved in the remedial work after drying out has taken place, or does the drying process remove the hazard? (as bacteria require both heat and water, therefore a reduction in relative humidity and water content of the screed would reduce the hazard). ??

Aud Thanks for reply. This was my line of thinking, but I just wanted some feedback. Thanks again.

I agree with the earlier comments. Builders and plumbers inevitably encounter contaminated parts of buildings in the course of their work and ought to know the simple methods to decontaminate such parts and also take appropriate hygiene measures in order to avoid/minimise the risk of infection to themselves, e.g. when replacing or repairing WCs. As for treating the contaminated (underfloor?) screed area, my strong guess is that the relevant measures would consist of physically removing any visible deposits and then applying a bleach solution. This would kill the smell and germs. Over time, depending on the degree of ventilation available, the screed would dry out and the bleach smell would dissipate. As regards the insurance company's request for a risk assessment (RA), perhaps it has a form with a tick box on it about RAs. That's fine for complex remedial work which merits prior thought and planning, but not for relatively simple tasks like the one described above. If the company uses a form with such a box, perhaps it has either been misunderstood by a clerical assistant who is unacquainted with basic building and plumbing matters or the reference to RAs needs amending with the addition of word like "where appropriate". On a wider scale, I've discerned from other postings on this forum that RAs are being required for various situations which simply don't merit them. Do others share this impression? If so, do such requirements arise because of 1) misperceptions by non-OS&H people about RAs, 2) some OS&H professionals being over-zealous and requiring everything and anything to be risk-assessed or 3) perhaps more likely a combination of 1) and 2) ?

With ref to #2 as some who has to deal with ‘radioactive or weird chemical content’ this looks fairly straight forward and I ‘d expect the plumbers to be able to deal with what looks like a standard procedure. It’s their job and so their RA, you might need to supply them with information about what is in the water (roughly, you can’t be expected to name every possible microorganisms that it contains). All they require is basic biological safety ie they wear some sort of PPE and maintain good hygiene.