Fat, Oil & Grease Legislation
grease trap legislation

What’s the legislation for fat, oil and grease management?

For existing premises the reasons for fitting a FOG management system tend to be as a result of drain problems, pressure from the local authority, landlord or environmental health. It is however a requirement under the Water Industry Act 1991 to ensure that your premises does not discharge any product into the drain which may interfere with its operation.

Taken from the Water Industry Act 1991

Provisions protecting sewerage system
111 Restrictions on use of public sewers
(1) Subject to the provisions of Chapter III of this Part, no person shall throw, empty or turn, or suffer or permit to be thrown or emptied or to pass, into any public sewer, or into any drain or sewer communicating with a public sewer- (a) any matter likely to injure the sewer or drain, to interfere with the free flow of its contents or to affect prejudicially the treatment and disposal of its contents
Thames Water reported that in 2007/2008 over 60,500 sewer blockages reported were caused in part by FOG.

With the cost running into Millions of Pounds Water Authorities are more and more adopting a 'polluter pays' principle where they will trace the problem back to the offender. The Thames Water website states "During 2007/08, we saw the continued success of the fat, oil and grease pollution prevention programme of targeting blockage hotspots, with a further 1,501 visits undertaken at food service establishments across our catchment."

For new-builds fitting a grease trap or grease removal system is a statutory requirement in the UK under Part H of the British building Regulations. Part H states under item 2.21 -
"Drainage serving kitchens in commercial hot food premises should be fitted with a grease separator complying with prEN 1825-1and designed in accordance with prEN 1825-2 or other effective means of grease removal."

PrEN 1825-1 (now BSEN 1825) is the European standard for gravity grease interceptors. The standard provides guidance purely for separators sizes where FOG is to be removed by gravity alone. Gravity separators are very large and not often practical for retro-fit. The British Building Regulations therefore takes a practical view and allows the use of "other effective means of grease removal" which can refer to biological dosing equipment or automatic grease separators.

Water UK - Best Management practice:

"Grease traps/grease interceptors Grease traps are specially designed units which are placed in drain pipes to separate the fat, oil and grease from the rest of the wastewater. The wastewater then continues to flow to the sewage works for treatment while the grease is retained in the trap to be collected by a licensed waste oil collector at regular intervals. These units can be highly effective if they are correctly installed, serviced and maintained.

A written record of maintenance must be kept. Your local environmental health officer may be able to assist on the location and size of the unit to suit your premises to ensure it is efficient at preventing the grease causing problems in the drains."


Water UK - Water UK
Building Regulations – Part H 2.21 Building Regulations Part H section 2.21Download Building Regulations Part H