Water Regulations and Cold Water Cisterns: What London Property Owners Must Do

The Water Supply (Water Fittings) Regulations 1999

The Water Supply (Water Fittings) Regulations 1999 (WSFR 1999) are the principal set of regulations governing the design, installation, and maintenance of water systems in the United Kingdom. They apply to all properties connected to the mains water supply — domestic, commercial, and industrial — and set out requirements for preventing waste, misuse, undue consumption, contamination, and erroneous measurement of water. They are enforced by the relevant water undertaker (Thames Water in London) and backed by criminal penalties for deliberate contravention.

For cold water storage cisterns, the key requirements are set out in Schedule 2 of the Regulations. A cold water storage cistern must be covered to prevent the ingress of light and foreign matter — the lid must fit closely and not allow openings sufficient for insects, rodents, or airborne contamination to enter. The cistern must be insulated to prevent warming of the stored water to temperatures at which Legionella bacteria can grow (above 20 degrees Celsius) and to prevent freezing. All pipe entries — the vent pipe and the overflow pipe — must be fitted with screens (fine mesh or similar) to prevent insects entering via these routes.

Schedule 2 Paragraph 16 in Detail

Paragraph 16 of Schedule 2 specifically addresses storage cisterns and states that every storage cistern shall be enclosed so as to exclude light and insects, be fitted with a cover, be insulated against heat gain and heat loss, and have all pipe connections screened to prevent entry of insects and vermin. The regulation also requires that cisterns be installed in a location where they can be inspected and cleaned, that they be adequately supported, and that they be constructed of materials that will not contaminate the stored water. Galvanised steel cisterns in contact with aggressive water — which London water can be in some zones — may not meet this last requirement and should be replaced with polythene or glass-reinforced plastic cisterns.

Who Is Responsible

The owner of the water system is responsible for compliance with WSFR 1999. In a privately owned property, this is the freeholder. In a leasehold flat, the obligation for common parts (including any shared water storage cisterns in the building) typically falls to the freeholder or management company, while the leaseholder is responsible for fittings and installations within their demise. For landlords, compliance with WSFR 1999 is a basic legal obligation and forms part of the broader duty of care to tenants. A landlord who knows that a cistern is non-compliant and fails to remedy it is in a precarious legal position if a water quality issue or Legionella incident arises.

Common Non-Compliance Issues in London

The most common non-compliance issues identified in London properties are: cisterns with lids that do not fit properly or that have been left off entirely; unscreened vent and overflow pipes through which insects and spiders have entered the cistern; no insulation jacket on an old cistern in an uninsulated loft; galvanised steel cisterns with visible internal corrosion; and cisterns that have been modified or extended with non-standard fittings that breach the sealed lid requirement. Any of these conditions should be remedied as part of routine property maintenance, and they should be identified and reported by a plumber during any loft plumbing work.

What Compliance Requires in Practice

Bringing a non-compliant cold water storage cistern into compliance with WSFR 1999 typically requires: fitting a close-fitting lid if one is absent or defective; fitting mesh screens to the vent pipe and overflow pipe; fitting a cistern insulation jacket (sides and top only — not under the cistern); and replacing the cistern if it is made of galvanised steel or has structural damage. For most London properties, the cost of bringing a modern polythene cistern into compliance by fitting a lid, insulation, and screens is £100 to £200. Replacing a galvanised steel cistern with a new flexible polythene cistern costs from £350. Prestige Engineers carry out cistern compliance upgrades and issue written compliance reports across all London boroughs.