Good evening Alan,
I hope you are well, this is my first post to the forum so you may have to be patient with my lack of forum etiquette,
My understanding of your situation is that you are
A) a registered charity
B) operating from a commercial or potentially industrial premises
C) allow either employee’s, public or others that you or the charity have a duty of care over
If all the above are correct under current legislation, it is within my opinion that you or the charity (if these are differing entities) are liable to carry out a risk Assesment in respect of the specific risk that your current premises poses. This, as raised by either a previous installer or consultant, is specific to wholesome, waste or stored water.
The best way in order to do so is to employ a competent individual or company to undertake the required risk assesment and if necessary make required advice on how to control the risks Typically by the following (but not limited too) : do nothing, alter the current installation to reduce or eliminate risk, have a system treatment implemented to reduce or eliminate risk or have a periodic control system implemented
I hope this is of some help to you and would suggest you seek the services of a competent company ideally who specialise in water treatment and risk assessing. This is common place within the commercial and industrial market.
I understand your lack of funding towards such services due to you being a small charity however I only make these suggestions as it would be considered in best practice at minimum and depending on circumstances a legal requirement to do so.
Please see the following documents to help with your issue:
HSE approved code of practice for the control of legionella bacteria in water systems (L8)
Health and safety at work Act (HASAWA)
I hope the above was a short and concise (as possible) answer to your question. I hope I didn’t repeat any earlier answers and should you require further assistance fee free to ask.
