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The Water Supply (Water Fittings) Regulations and Water Supply (Water Fittings) (Scotland) Byelaws, aim to protect public health, safeguard water supplies and promote the efficient use of water within customers' premises across the UK.

They set legal requirements for the design, installation, operation and maintenance of plumbing systems, water fittings and water-using appliances. They have a specific purpose to prevent misuse, waste, undue consumption or erroneous measurement of water and, most importantly, to prevent contamination of drinking water.

The Regulations apply in all types of premises supplied, or to be supplied with water, by a water undertaker.

They apply from the property boundary (usually at the stop tap and meter within the boundary box) to where the water is used in plumbing systems, water fittings and water-using appliances.

These regulations do not apply where a property has a private water supply and does not have a supply from a water company.

Owners, occupiers and anyone who installs plumbing systems or water fittings have a legal duty to ensure that their water systems comply with the Water Fittings Regulations.

If you want plumbing work within your property, we recommend choosing an Approved Plumber. This will give you confidence that the work is of a high standard and will protect the quality of your drinking water.

You can find a local WaterSafe approved plumber at or enter your postcode below and click submit.

Water Undertakers have a duty to enforce the Water Fittings Regulations within their appointed water supply areas. Water companies will undertake inspections of new and existing installations to check that the regulations are being met.

No current updates.

You can view the Water Supply (Water Fittings) Regulations 1999 here.

It is a requirement under the Water Regulations to notify IWNL if you are looking to make any of the changes below:

When Notification is required
1 The erection of a building or other structure, not being a pond or swimming pool.
2 The extension or alteration of a water system on any premises other than a house.
3 A material change of use of any premises.
4 The installations of:
(a) A bath having a capacity, as measured to the centre line of overflow, of more than 230 litres.
(b) A bidet with an ascending spray or flexible hose.
(c) A single shower unit (which may consist of one or more shower heads within a single unit), not being a drench shower installed for reasons of safety or health, connected directly or indirectly to a supply pipe which is of a type specified by the regulator.
(d) A pump or booster drawing more than 12 litres per minute, connected directly or indirectly to a supply pipe.
(e) A unit which incorporates reverse osmosis.
(f) A water treatment unit which produces waste water discharge or which requires the use of water for regeneration or cleaning.
(g) A reduced pressure zone valve assembly or other mechanical device for protection against a fluid which is in fluid category 4 or 5.
(h) A garden watering system unless designed to be operated by hand.
(i) Any water system laid outside a building and either less than 750mm or more than 1350mm below ground level.
(5) The construction of a pond or swimming pool with a capacity greater than 10,000 Litres which is designed to be replenished by automatic means and is to be filled with water supplied by the water undertaker.

You can notify IWNL by completing a Regulation 5 Notification form.