The burial plot should be away from the house and away from services such as drainage, cables and gas supplies. This is especially important if any extensions or repairs are carried out in the future, to avoid disturbing the remains.
The burial plot should be deep enough to prevent foraging animals from disturbing the body, and should have at least one metre of subsoil below its base and at least one metre of soil above the coffin. The grave should not contain any standing water when it is first dug and should not be dug in very sandy soil. This should reduce the likelihood of the walls of the grave caving in when excavating the ground.
Further advice on groundwater pollution and where to position burial plots in sensitive areas is available on the GOV.UK - Cemeteries and burials website.
The Environment Agency have intervention powers if there is a risk of pollution to groundwater or a nearby watercourse, so it is worth checking with them beforehand. Find contact details on the Environment Agency website.