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In most UK commercial leases, the tenant is responsible for the day-to-day cleaning and emptying of the grease trap, because they operate the kitchen that produces the fat, oil and grease (FOG). The landlord is often responsible for the trap itself and for the shared drainage it discharges into. However, responsibility is ultimately set by the specific lease — and under the Water Industry Act 1991 the landlord can still be pursued by the water company if FOG from the premises blocks the public sewer. The only reliable approach is to check the lease and put independent monitoring in place so both parties can prove compliance.
What the lease usually says
Most commercial leases make the tenant responsible for cleaning and emptying the grease trap, while the landlord retains responsibility for the repair or replacement of the trap and for the communal drainage infrastructure. Some leases make the landlord responsible for all drainage maintenance; others split responsibility between the parties. There is no universal rule — the wording of the lease clause decides who is liable, so never assume.
Why the landlord is still exposed
Even where the tenant is contracted to clean the trap, a blockage in shared pipework remains the landlord’s problem. Water companies pursue the party responsible for the drainage that enters the public sewer, and under the Water Industry Act 1991 it is an offence to allow matter that impedes the flow of the sewer to enter it. Penalties can reach £50,000 in the Magistrates’ Court and are unlimited in the Crown Court, and water companies can also recover remediation costs. That is why landlords with food and beverage tenants increasingly commission independent FOG monitoring rather than relying on tenant goodwill.
What good practice looks like
- A lease clause that explicitly mandates the grease trap type, servicing frequency and record-keeping.
- Independent quarterly inspection with photographic evidence.
- A shared compliance record that both landlord and tenant can rely on.
- A clear escalation route if a tenant repeatedly fails to maintain their trap.
Frequently asked questions
Is a grease trap a legal requirement in the UK?
Commercial kitchens must prevent FOG from entering the drainage system, and equipment should meet standards such as BS EN 1825. In practice, most water authorities expect a grease trap or separator to be fitted on premises producing hot food.
Who pays for a new grease trap — landlord or tenant?
Typically the landlord owns and replaces the trap while the tenant maintains it, but this depends entirely on the terms of the lease.
What happens if neither party maintains the grease trap?
The likely results are blockages, odours, possible closure and enforcement action — followed by a dispute over who is liable. Documented independent monitoring prevents both the blockage and the argument.
Not sure who is liable on your site?
Magneté runs independent FOG inspections that give both landlord and tenant clear proof of compliance across single sites or whole estates. Book a free strategy call to review your grease-trap responsibilities and risk.
