If you think there might be something wrong with your private water supply, stop using it and try and find out what has happened.
You might want to use bottled water until you can find out what the problem is and how to fix it.
You can ask your local council for help with this.
Depending on what's happened, they will be able to give you advice about what to do.
Your local council can also give you advice on whether your water would be safe to use with more treatment (e.g. boiling), or if you should stop using it.
If you use a company for maintaining your UV filters, they can be a good source of information too.
You can ask the council to check your supply once you have fixed the issue to make sure it's safe to drink.
It's a good idea to make a list of any major things that could go wrong with your supply so you're prepared.
For example, if your supply is near a road, what would happen if there was a fuel spill?