Why having your private water supply tested is important
Testing only reflects the composition of the water at the time when the sample was taken.
This means it's only a snapshot of your supply quality that day. It doesn't guarantee water quality over time.
But it's important in showing that the treatment you have installed works well, and that the water coming out of your tap is safe to drink.
A failed water sample means that your treatment might not be as effective as you think it is.
Even if your supply passes a test, it doesn't guarantee that it will be safe to drink all the time.
You should use a risk assessment to identify any risks that mean your supply could be unsafe.