Private Water Supplies

What is a private water supply?

A private water supply is a supply not provided by a water company such as Thames, Southern or South East Water. Approximately 1% of the population in England and Wales has a private water supply to their homes. Most private water supplies are in rural locations and are from wells, boreholes, springs or streams. 

What is a private distribution network?

These private water supplies occur when the water undertaker or licensed supplier provides a mains water supply to the boundary of a primary premises, whereafter the water is distributed via a private distribution network to further privately owned buildings/properties.

What are the implications of the Private Water Supplies (England) Regulations 2016 (as amended)?

The Private Water Supplies (England) Regulations 2016 (as amended) cover all private water supplies and private distribution systems. They came into effect in June 2016, replacing The Private Water Supplies Regulations 2009 which came into effect in January 2010, and look to safeguard public health by ensuring that supplies are wholesome, meaning safe to drink, and sufficient. 

Private water supplies are categorised into four groups:

I.     Single private dwellings. 

II.    Small domestic supplies supplying fewer than 50 people. 

III.   Large domestic supplies supplying over 50 people or serving commercial premises, including B&B's, food businesses, public buildings and holiday/private lets. 

IV.   Private distribution systems where mains water is used to supply a primary residence, then is further distributed via a private network of distribution pipes to one or more privately owned, secondary premises.

Risk assessments and sampling requirements

The regulations require the council to carry out a risk assessment of private water supplies at least once every five years. This involves surveying the supply to identify potential contamination risks from the source to the consumer's tap, identifying possible prevention measures and treatment options. This will determine which parameters need to be sampled for and the frequency of sampling. 

For each of the following categories of supply the following actions can be expected: 

I.     Single Private Dwellings: Single private dwellings will not require routine monitoring or a risk assessment, unless they are rented to a third party in which case they will be classified as commercial premises. Sampling or risk assessment          can be undertaken at the owner's request.  

II.    Small Domestic Supplies: The amount of monitoring will depend on the outcome of the risk assessment, however it will be a minimum of once every five years. Supplies will be monitored for five basic parameters and anything else that         arises from the risk assessment.  

III.   Private Distribution Systems: Monitoring must be carried out according to the outcome of the risk assessment.

IV.   Large Supplies or Commercial Premises: Two types of monitoring will occur on these supplies: 

  • 'Group A' monitoring tests the wholesomeness of the water; the frequency of monitoring Group A parameters will depend on the amount of water used.

  • 'Group B' monitoring determines whether or not the water supply meets the required legal standards. The range of Group B parameters which may be monitored is extensive and the amount of monitoring depends on the outcome of the risk assessment.

It is likely that the majority of large supplies will have two samples analysed per annum.

Investigation and action in the event of a failure

Any sample that fails to meet the prescribed concentrations will result in the supply being investigated to try and determine the reason for this failure. If a wholesome supply cannot be achieved through implementing physical changes to the supply network, then additional or upgraded water treatment apparatus may be required.


In the event of a failure, where a supply is found to be unwholesome, action is sought to remedy the problem/s. An improvement notice may be served that specifies the improvements to be made to the supply, the persons who should carry out the work and when this work should be completed by. In the event of a failure that is liable to cause an immediate risk to human health, a notice will be served that places a restriction or prohibition on the use of the supply. Failure to comply with a notice may result in prosecution in the Magistrates' or Crown Court.


Appeals can be made to the Magistrates' Court or the Secretary of State depending on which notice is served.

Frequently asked questions 

What is a commercial/large supply?

The commercial/large category includes any business that supplies water from a private water supply to the public for drinking, washing, food preparation, or where the water is used in a way that it is likely to enter the human chain (e.g. dairies washing down equipment). This category includes B&Bs, holiday lets, pubs, public buildings and food production premises. Also within this category are domestic private water supplies that are rented to tenants and/or provide water to more than 50 people.

What if the supply outlet is not on my land?

The owner of the private water supply is responsible for providing safe water to the users even if the supply outlet (tap) is not on the owner's land.

Can I do the risk assessment and sampling myself?

Risk assessments can only be performed by the local authority or a company the local authority has appointed and authorised to act on its behalf.

The local authority is responsible for ensuring sampling is completed according to legislative requirements, therefore if you want another company to take and analyse samples of your private water supply, the local authority will need to approve the sampling company and analysis suite prior to samples being taken. The analysis must comply with the new legislation. The local authority will need to be sent the result certificates directly from the laboratory.

Can I build up an immunity to my water as I have drunk it for years and it hasn't done me any harm?

People can build up resistance to bacteria, however a wholesome supply is always required as visitors may not have had any time to build up immunity. The young or unwell are likely to be affected the most. Studies show that children under 10 years old, whose homes have a private water supply, are nearly four times more likely to suffer from diarrhoea than other children.