Private water supplies from a well, borehole or spring now will have to be tested for its quality. Any test failure is likely to require replacement of old piping, installation of a UV filter or new surface water run-off arrangements.
Farms, hotels, caravan parks and holiday lets, plus supplies to large domestic areas (typically shared by 50 people or more) will need a full risk assessment to be carried out within five years, and sampling/analysis once a year.
Many local authorities will be asking for completed risk assessment forms and there are businesses that will complete the assessment for you, including monitoring and sampling.
It could also be advisable to seek legal advice too about your private water supply.