These types of private water supplies draw their water from deep underground and are less likely to be contaminated with micro-organisms, though they may contain minerals and other chemicals. Underground sources are at risk of contamination at the surface extraction point where surface water may gather or flow in to the supply. Shallow wells are also susceptible to contamination carried by surface water or activities such as fertilizer spreading.

These types of private water supply can be contaminated by micro-organisms especially during periods of rainfall. Rainwater can run across the ground collecting contamination from, for example, soil or animal droppings which is then deposited in to the water. Surface sources also dry up during prolonged periods without rain.

There is another type of private water supply known as either an ‘onward distribution’ or ‘private distribution’ network. In this situation a water company sells water to an individual who then further distributes it through their own pipe network to other properties not in their ownership. The individual paying the water company will usually distribute the water at a cost to the consumer. Such networks are also classed as private water supplies under the private Water Supplies (Wales) Regulations 2017.

If you are a householder, (owner occupied or privately rented), commercial premises or food business and you have concerns about your private water supply drinking water, please email the Council at water@flintshire.gov.uk. for advice. Also consider boiling your water prior to drinking, teeth brushing and using for food preparation or purchase bottled water in the interim, until the issue is resolved.

The responsibility for making sure the water supply is maintained is with the owner, or collective owners.

Users of the supply should be aware of what can influence the water supply and should find out the answers to the following questions to make sure the water supply is safe to drink:

• Who is responsible for the upkeep and maintenance of the supply, particularly any treatment equipment? (one person or split between several owners equally)
• Who is the nominated contact for the supply in the event of an issue?
• Where is the water taken from and is anything necessary to protect this source?
• Are there any rights of access that need clarification for all the users?
• How does the water get into your property and do the pipes need maintaining?
• Is the water treated and is the equipment in good working order and regularly maintained?
• Who pays for any repairs?
• What is the contingency plan in case the water is unavailable or unfit for consumption?

All parts of the supply should be regularly inspected, including the catchment area. The inspection should include checking for damage, or for the presence of anything which may affect the water quality.

Private water supplies can become contaminated with a range of micro-organisms, also known as bacteriological, and chemicals.

Anyone who consumes water contaminated with micro-organisms is at risk of infection which can result in a number of serious illnesses. The risk is especially high for people who are not used to your water. If your pets drink the water they too may become infected and this infection could be transmitted to humans.

For example, Escherichia coli (E.coli) and Enterococci are bacteria found in the gut of warm-blooded animals. They should not be present in drinking water and, if found, immediate action is required to identify and remove any source of faecal contamination. The standard is 0 per 100ml.

Private water supplies can also become contaminated as a result of chemicals:

• being used in farming or other land management areas (for example pesticides);
• occurring naturally in the ground (mainly minerals, such as iron) which may affect the appearance/taste of the water and can reduce the effectiveness of treatment equipment;
• being used in industrial or commercial processes (for example solvents).

Lead contamination

Lead may be present in your water as a result of the plumbing at the property (where there are older lead pipes or holding tanks, or lead solder has been used on copper pipes). While there are treatment methods available to deal with lead, it is best to replace any lead plumbing. Water that has been left to stand in lead pipes for long periods (for example overnight) should be left to run out of taps for approximately one minute before using. 

If you need further advice or would like your water testing for lead, contact water@flintshire.gov.uk

All private water supplies can pose a threat to health unless they are properly protected and treated. You may not be able to tell whether your water is safe as contamination may not show as smell, taste or colour of the water

The drinking water from a mains supply goes through several intensive purifying processes at the treatment plant before reaching consumers. This is often not possible with private water supplies, However owner(s) should consider installing a water treatment system on the supply as these systems can ensure the supply is safe to drink. Micro-organism contamination can usually be treated by filtering the larger impurities; followed by ultraviolet (UV) sterilisation. 

Both filtration and UV sterilisation systems do require regular maintenance to be effective. 

If you share your supply with other properties, it is possible to have the treatment within the catchment area, rather than in each house. 

If you have lived at your property for many years, you may have developed a level of immunity to some of the bacteriological contaminates in your supply. However, treatment should still be carried out because any visitors may not have immunity, especially the elderly or very young children.

A treatment equipment supplier will be able to discuss treatment options with you, although they may need to test the supply first, in order to supply accurate advice.

The Council can provide examples of companies who can provide quotes, if required.

If there is already treatment in place on your private water supply, it is recommended that consumers and other relevant persons keep up-to-date with operational checks and ensure that maintenance is being carried out (for example replacing UV lamps, regularly changing filers or monitoring chlorine dose).  Also it is good practice to keep a sufficient stock of spares of essential equipment, to ensure the supply remains wholesome at all times.

Without putting yourself at risk, if you can safely access your water source, it is wise to check that the source is adequately protected and secure from contamination, from flooding, pooling of water around the head of the chamber and secure from animal access.

Commercial premises and landlords for privately rented properties should document any actions taken, and if required, present these to the Local Authority to confirm that the supply did not present a risk to health during any exceptional circumstances.