Private Water Supplies - Frequently asked Questions

Below are a selection of frequently asked questions regarding private water supplies, risk assessments and the sampling process. If you cannot find the information you are looking for you can fill out our online form or contact our Environmental Health team at

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 food chain. This category includes rented properties, B&B, holiday lets, pubs, food production premises. Also within this category are domestic private water supplies using more than 10 cubic metres of water per day.

Can I do the risk assessment and sampling myself?

Risk assessments can only be performed by the local authority or by persons the local authority has deemed competent. The local authority is responsible for ensuring sampling is completed according to legislation, therefore if you would like another company to take and analyse samples of your private water supply, the local authority will need to approve the sampling company and the parameters to be analysed, 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.

Why do you need a risk assessment of your private water supply?

A risk assessment is needed to:

  • protect public health
  • maintain public/customer confidence in drinking water
  • identify the legal duty and the responsibility of the water supplier.

The risk assessment will illustrate how to minimise the potential risks to your supply and to human health, and provide adequate information to allow audit monitoring parameters to be identified.

On completion of your risk assessment we will explain how often the supply needs to be sampled, based on the risks identified. Every five years the risk assessment will be reviewed. You will receive the assessment report and a copy will be retained for 30 years at the council.

The Private Water Supplies Regulations impose a tighter legal duty for monitoring of your supply, and one of the functions of the risk assessment is to identify any parameter (that is: types of bacteria, chemicals for example) which could pose a potential risk to human health. The parameters identified can then be monitored.

How long will the assessment take?

The risk assessment will typically take approximately two hours. Ideally the person responsible for the supply should be present so that the risk assessment can be conducted as quickly and efficiently as possible. During the risk assessment we will need access to the source of the supply i.e. borehole, well, or spring, any collection chambers, holding/storage tanks including header tanks which may be found in roof spaces, and finally the point of use of the supply.

How much will the risk assessment cost?

Please take a look at our fees and charges

How regularly will my supply need to be sampled?

Single private dwelling No requirement - sampled at the request of the owner/occupier
Small domestic supplies (more than 1 address served)   At least once every five years or more frequently if the risk assessment identifies a need.
Private Distribution System Dependent on need, identified by risk assessment
Large or commercial supplies To be determined by the volume of water supplied but at least twice per year.

Why should I register my private water supply with the local authority?

So that we can:

  • carry out risk assessment and monitoring if required under the The Private Water Supplies (England) Regulations 2016 as amended.
  • advise the appropriate agencies to ensure there is no risk to your supply’s catchment area (for example, advising persons undertaking bio-solid spreading on land that there are private water supplies which may be affected)
  • inform you of potential contamination threats to aquifers that may serve your supply
  • notify you of any updates of legislation involving private water supplies and your responsibilities.

You can register your supply by sending your details to our Environmental Health time at

How can I keep my supply safe?

All parts of your supply should be routinely monitored and inspected to ensure that it is in good working order, and has not been interfered with or damaged. Any products or treatment used on the supply must be featured on the DWI list of approved products. The supply must be appropriately protected throughout, from source to point-of-use.  This should include a maintenance programme to clean the distribution system and storage tanks or header tanks, and to ensure that any treatment works are operating as they should and according to manufacturer’s guidelines.

What if I supply water to others?

If you supply water to others with or without a charge, for example other domestic premises, renting out holiday accommodation or to commercial premises with employees or food production it is your responsibility to ensure the water is wholesome and does not pose a risk to human health.

Should I get my supply checked by the Borough Council?

Unless your supply serves a single domestic dwelling, your supply will be risk assessed and monitored by the council in the next five years. However, if you suspect that something is wrong with the supply or you would like to request a sample to be taken and analysed you can contact Environmental Protection to discuss your concerns and to arrange for any sampling to be carried out.

Further guidance on the Private Water Supplies Regulations (England) Regulations 2016 (as amended) is available on the Drinking Water Inspectorate website

What are the different categories of private water supplies?

Large supplies - a water supply serving over 50 people; or produces more than 10 m³ per day of water; or is used for commercial purposes, for example, rented properties, holiday lets, a bed and breakfast; or is public premises. These supplies require sampling at least once a year and a risk assessment undertaken every five years. If you are a tenant in rented accommodation that is served by a private water supply, please check with your landlord, or us, that the private water supply is registered with us so we can check that the water supply is wholesome and safe to drink.

Small supplies- a water supply serving two or more premises; produces less than 10m³ of water; and is not used for commercial purposes, or for public premises. These supplies require sampling and a risk assessment every five years.

Single supplies - a water supply that serves only one private domestic dwelling where no commercial activity takes place. (Rented properties would not fall into this category because of the commercial use). These supplies will only be sampled and risk assessed at the owner's request. This is often requested when people are looking to buy a property on a private water supply.

Private distribution systems - a water supply that is supplied by a water company and then further distributed by the account holder to a third party, for example, caravan parks. These supplies require a risk assessment every five years and sampling at a frequency dependent of the outcome of the risk assessment.

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