Do I need a grease trap for my café or restaurant?

If you prepare food commercially, you're responsible for keeping fats, oils, grease and food waste out of the sewer — Thames Water says discharging them is illegal — and a local authority can order you to install a grease trap under the Building Act 1984. Where separation is needed, BS EN 1825 is the recognised standard, and the separator has to be sized to your kitchen's flow and serviced to keep working. Whether you need one, and what size, depends on the kitchen — get a site survey rather than guessing.

Commercial Plumbing in Ealing | Verified Plumbers

Commercial plumbing isn’t domestic plumbing scaled up. The moment water serves a business, the law starts asking questions a home never faces — backflow, Legionella, trade effluent, grease and commercial gas — and getting them wrong can mean enforcement, disruption or, in serious cases, closure.

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Coverage: W3, W5, W7, W13, UB1, UB2, UB5 and UB6, plus the NW10 fringe around Park Royal and North Acton — restaurants and takeaways, shops and salons, offices, care and education premises, HMOs and managed blocks, and the borough’s light-industrial estates.
What this covers: commercial and non-domestic plumbing — backflow protection and RPZ work, grease management, trade effluent pipework, hot and cold water services, Legionella-related plumbing, and commercial gas routed to a suitably qualified engineer.
Not this page: a blocked drain or sewer is blocked drains; a boiler or heating fault is boiler repair or central heating repair; a hidden leak is leak detection. Gas you can smell is the emergency line above, not a directory search.
Costs: planned maintenance or reactive call-out, with compliance work priced separately — see what it costs.
Availability: listings show who covers your postcodes and works on commercial premises — confirm scope and qualifications when you book.

Jump to: What commercial plumbing covers · On the first visit · Compliance is the job · Grease, fat and the drains · By district · Whose responsibility? · Costs · FAQs

What commercial plumbing actually covers

What makes a job “commercial” is the duties and the use, not the diameter of the pipe. The same washbasin in a house and in a busy restaurant can sit in completely different regulatory worlds, because the risk the water poses — and who is legally responsible for it — changes the moment the premises is run as a business.

In Ealing that spans a wide range: catering kitchens in restaurants, takeaways and pubs; shops, salons and dental or veterinary surgeries; offices and mixed-use buildings; care homes, schools and nurseries; HMOs and managed residential blocks where a landlord or agent controls communal water; and the light-industrial units on the borough’s estates. The recurring threads are higher contamination risks (and so higher backflow categories), Legionella duties in stored or recirculated water, grease where food is prepared, trade effluent where a process discharges to the sewer, and commercial gas categories where appliances are bigger than domestic. The sections below set out each — and, importantly, when each does and doesn’t apply, because none of them is universal.

On the first visit — and the everyday jobs

Before any work, a commercial plumber’s first job on site is to understand the premises, not just the fault. That means finding the incoming supply and the isolation points, working out who the duty holder is and what the lease makes the tenant responsible for, checking the backflow protection, the hot-water storage and any dead legs, tracing the waste route and any grease equipment, and — crucially — judging whether the work can be done without stopping trade. On a premises that can’t simply close, that last point shapes everything: temporary isolation, a safe interim repair, or out-of-hours and phased work to keep you trading.

The everyday callouts are less exotic than the compliance list suggests: commercial sinks blocked with grease, a failed thermostatic mixing valve, leaking staff or customer WCs, hot-water capacity that can’t keep up at peak, a seized isolation valve that won’t shut, or a booster or pump set that’s given up. Some of this is straightforward plumbing; some is specialist compliance work — a formal Legionella risk assessment, RPZ testing, a commercial gas safety inspection — which a plumber may carry out where qualified or bring in a specialist for. Either way, ask for the paperwork at the end: service records, RPZ test certificates, gas safety records, grease-trap service notes and any trade effluent documentation are what prove the duty’s been met if anyone asks.

Compliance is the job, not an add-on

This is where a good commercial plumber earns their fee — not in the pipework, but in knowing which of these duties bite on your premises and which don’t.

Backflow and contamination. The Water Supply (Water Fittings) Regulations 1999 require every system to prevent contaminated water flowing back into the mains.⁶ Risk is rated in five fluid categories, from wholesome (1) to a serious health hazard (5), and the category a commercial system sits in is often higher than a home’s — depending on what the water is used for. The device steps up with the category: a single check valve covers fluid category 2 and a double check valve up to category 3,⁴ while a reduced-pressure-zone (RPZ) valve is rated to category 4 — and must be notified to the water undertaker and tested at least once a year — and category 5 needs a physical air gap, because no mechanical device alone is accepted at that level.⁵ Things like commercial hose-union taps, certain catering equipment and process connections can fall into category 4 or 5. Your water undertaker categorises the system and has the final say.

Legionella. Where a water system could create a risk of exposure to Legionella, whoever is in control of the premises has a duty under the Health and Safety at Work etc. Act 1974 (with COSHH and the Management Regulations) to assess and control it. HSE’s Approved Code of Practice L8 is the benchmark: identify and assess the risk, put a written control scheme in place where needed, keep records, and appoint a competent “responsible person”.⁷ The duty holder is usually the employer or occupier, and can be the landlord or agent in a multi-let building — it depends on who controls the system and what the lease says. It’s risk-assessment-led, so a small shop with a simple, well-used system is a lighter touch than a care home, a building with stored water, or anything with cooling or spray.

Trade effluent. If your business discharges anything other than ordinary domestic sewage to the public sewer — liquid produced by a trade or industrial process, for example food production, vehicle washing or certain manufacturing — you may need a trade effluent consent. Thames Water is the sewerage undertaker for Ealing, and it’s clear that a consent is a legal document issued under the Water Industry Act 1991, that discharging trade effluent without one is an offence, and that the consent sets conditions and limits on the discharge.⁸ Most shops and offices won’t need one; a production or process discharge might — it’s entirely activity-dependent, so check before you connect.

Commercial gas. All gas work must be carried out by a Gas Safe registered business under the Gas Safety (Installation and Use) Regulations 1998. Commercial appliances, larger pipework and gas consumption sit outside domestic categories, so the engineer needs the relevant non-domestic or commercial work categories — which you can check on the back of their Gas Safe card or via the Gas Safe online register.² A commercial catering engineer also carries out specific checks — including air testing and confirming ventilation works with the appliances running — and you may be asked to show records that this has been done.³ For a gas smell or suspected carbon monoxide, treat it as an emergency and call the National Gas Emergency Service on 0800 111 999: carbon monoxide can’t be seen, smelled or tasted, so if an alarm sounds or you suspect it, get fresh air, turn the appliance off if it’s safe, leave, call, and get medical advice.¹

Grease, fat and the drains

For any premises that prepares food, this is the duty most likely to land you with a blockage, a bill or enforcement. Thames Water is unambiguous: discharging fats, oils, grease and food waste to the sewer is illegal, the business is responsible for disposing of them legally and safely, and professional kitchens are a big cause of blockages in its region.⁹ It also points out two powers worth knowing: a local authority can order you to install a grease trap for any building used for your business under the Building Act 1984, and can inspect how you manage kitchen waste under food-safety law.⁹

Where grease separation is the answer, the recognised standard is BS EN 1825 — Part 1 covers the separator’s design, performance and testing, and Part 2 covers selecting the right nominal size, plus installation, operation and maintenance.¹⁰ Two things follow from that. A separator only works if it’s sized for the kitchen’s flow, so it’s a site-survey job, not a one-size box. And it only keeps working if it’s serviced — an unmaintained trap is the most common reason a premises that “has a grease trap” still blocks the sewer and ends up in front of the enforcement team. Good kitchen practice (scraping plates, never pouring fat down the sink, strainers in the gullies) reduces the load but doesn’t replace the equipment where it’s required.

Commercial plumbing across Ealing’s premises

For commercial work the premises and its use matter far more than the postcode — a fried-chicken takeaway, a dental surgery and a warehouse on the same road face different rules. Across the borough the patterns fall out roughly like this.

Acton (W3, NW10). The borough’s industrial heavy-hitter sits here: Park Royal and North Acton, one of London’s largest industrial areas, full of food-production and light-industrial units where trade effluent, larger pipework and commercial gas all come into play — and on a food-production or process unit, the plumber should confirm whether a discharge is ordinary foul waste or trade effluent before connecting equipment. Acton High Street adds the other Ealing staple — restaurants and takeaways trading below and beside flats, where grease management and shared waste stacks are the recurring issue; in a parade with flats above, a kitchen blockage can involve a shared stack or rear waste run, so access and responsibility need confirming before work starts.

Ealing (W5, W13). Ealing Broadway’s offices, restaurants and mixed-use blocks. The compliance mix here is Legionella in managed and communal water systems and FOG in the food units, often in buildings where a managing agent controls the shared services.

Greenford (UB6). Greenford’s industrial estates plus the Greenford Broadway parade — a blend of light-industrial premises (trade effluent, bigger systems) and high-street catering needing grease management.

Hanwell (W7). The Broadway parade of smaller cafés and shops. Food premises still need grease management, and the tight rear access behind older parades makes separator siting and servicing the practical headache.

Northolt (UB5). Light-industrial units and local parades, frequently with shared service areas and yards, so access and shared pipework need confirming before work starts.

Perivale (UB6). The Perivale industrial estate off the A40 — trade and industrial premises with larger systems, where trade effluent consent and backflow categories above domestic are most likely to apply.

Southall (UB1, UB2). The Broadway and South Road have many food and retail premises, so grease management and shared rear-waste runs behind older parades are the recurring theme — and where access is through a shared yard, a grease separator’s siting and servicing need sorting before anyone commits to a fix.

One borough-wide point for commercial drainage: the council’s Infrastructure Delivery Plan records that Ealing carries flood risk from sewer overflows and capacity issues, and that the River Brent — a main river — runs through the borough.¹¹ So getting commercial waste, and any process discharge, connected to the right system matters: a wrong connection is a pollution risk as well as a blockage waiting to happen.

Whose responsibility — leases, landlords and duty holders

Commercial premises rarely work like a home, where the landlord’s repairing duty is set by statute. Here, the lease usually decides.

Many commercial leases are “full repairing and insuring” (FRI), which typically puts repair and maintenance of the premises — including its plumbing — on the tenant. And Section 11 of the Landlord and Tenant Act 1985, which makes a residential landlord keep the water, heating and sanitation installations in repair, applies to dwellings and does not generally extend to commercial tenancies.¹² So for a business premises it’s the lease, not Section 11, that decides who fixes what.

Two duties sit slightly apart from the repairing question. Legionella control and gas safety fall on whoever is in control of the premises and the systems — which can be the occupier, the landlord, or a managing agent, depending on the arrangement — so a tenant can carry the day-to-day duty even where the landlord owns the building. This is general information to help you ask the right questions, not legal advice: read your lease, and take proper advice where the position isn’t clear.

What it costs

Commercial work is priced differently from domestic. Many premises run a planned-maintenance arrangement (a fixed visit schedule) rather than waiting for a fault, and the bigger compliance items — RPZ testing, a Legionella risk assessment, grease-separator servicing, a commercial gas safety inspection — are usually quoted as separate pieces of work, not folded into a call-out. Premises that can’t simply close (kitchens, care homes, surgeries) often pay an out-of-hours premium to have work done outside trading times.

Work	Indicative cost (editorial estimate)
Reactive commercial call-out / repair	£80–£150+ per hour or visit
RPZ valve annual test	£80–£180
Legionella risk assessment (smaller premises)	£150–£400
Grease trap / separator service	£100–£300+
Commercial gas safety inspection (catering / boiler)	£120–£400+

Editorial estimate only, for orientation. These are NOT regulated rates, NOT market data and NOT a published cost survey — premises, system size, frequency and how much compliance work is involved change everything. Always confirm scope and price before booking.

There is no official price list for commercial plumbing in Ealing. Local cost context: the borough is inside London’s ULEZ¹³, and around half its road network sits in controlled parking zones, with 54 CPZs across the borough¹¹ — a contractor’s vehicle costs and parking may show up on the bill. To read a quote line by line, see how to read a plumbing quote.

Frequently asked questions

It’s the use and the duties, not just the size of the pipe.

Once water serves a business, you can be into higher backflow fluid categories, a Legionella duty on whoever controls the premises, trade effluent if a process discharges to the sewer, grease management in a kitchen, and commercial gas categories where appliances are bigger than domestic.

None of these is automatic — which ones apply depends on your premises and what you do there — but a commercial plumber’s real job is knowing which bite on you.

If you prepare food commercially, you’re responsible for keeping fats, oils, grease and food waste out of the sewer — Thames Water says discharging them is illegal — and a local authority can order you to install a grease trap under the Building Act 1984.⁹

Where separation is needed, BS EN 1825 is the recognised standard, and the separator has to be sized to your kitchen’s flow and serviced to keep working.¹⁰

Whether you need one, and what size, depends on the kitchen — get a site survey rather than guessing.

Thames Water — what not to flush or pour down the drain

Only if you discharge more than ordinary domestic sewage to the public sewer — liquid produced by a trade or industrial process, such as food production or vehicle washing.

A trade effluent consent from Thames Water is a legal document under the Water Industry Act 1991, and discharging trade effluent without one is an offence, with conditions and limits set in the consent.⁸

Most shops and offices won’t need one; a production or process discharge might, so check with Thames Water before you connect.

Whoever is in control of the premises and the water system — often the employer or occupier, and sometimes the landlord or managing agent in a multi-let building, depending on the lease.

HSE’s Approved Code of Practice L8 expects a risk assessment by a competent person and, where the risk warrants it, a written control scheme, records and a named responsible person.⁷

It’s risk-assessment-led, so how much is involved depends on the system and the premises — a simple, well-used system is a lighter touch than stored water, cooling or spray.

HSE — Legionnaires’ disease

Usually the lease, not statute.

Many commercial leases are full repairing and insuring, or FRI, which typically puts repair and maintenance — including plumbing — on the tenant.

Section 11 of the Landlord and Tenant Act 1985, which makes a residential landlord keep water, heating and sanitation in repair, applies to dwellings and doesn’t generally extend to commercial tenancies.¹²

Legionella and gas duties separately fall on whoever controls the premises.

Read your lease and take advice where it’s unclear — this isn’t legal advice.

Landlord and Tenant Act 1985 — Section 11

Yes.

All gas work must be done by a Gas Safe registered business under the Gas Safety (Installation and Use) Regulations 1998, and commercial appliances, larger pipework and commercial catering need the relevant non-domestic or commercial work categories — which aren’t the same as domestic qualifications.

Check the back of the engineer’s Gas Safe card or the Gas Safe online register for the right categories.²

For a gas emergency or suspected carbon monoxide, call the National Gas Emergency Service on 0800 111 999.¹

Gas Safe Register — check an engineer

Why verified plumbers — not a general directory

With commercial premises the stakes are higher: downtime costs money, and a compliance failure on backflow, Legionella, grease or gas can mean enforcement or a closed business. Every listing here is checked before going live and re-verified annually — we confirm the business is legitimately trading and verify the named contact, we check evidence of public liability insurance, and we confirm the plumber covers Ealing’s W and UB postcodes and works on commercial premises before a profile is approved.

For gas work you can confirm an engineer’s commercial categories yourself on the Gas Safe register, and for water-fittings work any plumber can be looked up on WaterSafe, the free, water-industry-backed national register. Profiles may be suspended or removed if credentials lapse or credible concerns are raised — see the full verification process →

There’s no pay-to-play ranking of listings and no customer middleman fee: enquiries go directly to the plumber.

Related areas

Verified commercial plumbers across Ealing’s neighbourhoods, including:

Acton
Brentham Garden Suburb
Central Greenford
Dormers Wells
Ealing Broadway
Ealing Common
East Acton
Greenford
Greenford Broadway
Hanger Hill
Hanwell
Hanwell Broadway
Lady Margaret
Montpelier
North Acton
North Ealing
North Greenford
North Hanwell
Northfields
Northolt
Northolt Mandeville
Northolt West End
Norwood Green
Perivale
Pitshanger
South Acton
South Ealing
Southall
Southall Broadway
Southall Green
Southall West
Walpole
West Ealing

Related services

Other verified plumbing services in Ealing:

Related guides

Commercial plumbing in Ealing is less about the pipework than about getting the duties right — the correct backflow protection for your fluid category, Legionella controlled by whoever holds the duty, grease and trade effluent handled legally, and gas work done by an engineer with the right commercial categories. The verified plumbers listed above work to those standards, so a small job doesn’t become an enforcement problem.

Contact verified commercial plumbers in Ealing ↑

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Last reviewed: June 2026 by Adiel Khan — SFEDI-accredited business advisor 20+ years experience (South East Enterprise Ltd) and operator of VerifiedPlumbers. LinkedIn ↗

This page is checked for compliance and regulatory accuracy against the regulations and bodies cited on this page, including the Gas Safety (Installation and Use) Regulations 1998, Gas Safe Register, the National Gas Emergency Service, HSE Approved Code of Practice L8 (Legionella), the Health and Safety at Work etc. Act 1974, the Water Supply (Water Fittings) Regulations 1999 and WaterRegsUK, the Water Industry Act 1991 (trade effluent), the Building Act 1984, BS EN 1825, Section 11 of the Landlord and Tenant Act 1985, Thames Water, Ealing Council and Transport for London. Source links are provided within this page where relevant.

Sources & further reading

National Gas — Emergency contacts (gas leak and carbon monoxide: call 0800 111 999; emergency steps) — https://www.nationalgas.com/emergency-contacts
Gas Safe Register — Gas Safe ID card categories (domestic vs non-domestic / commercial work categories) — https://www.gassaferegister.co.uk/gas-safety/the-gas-safe-id-card/the-gas-safe-id-card-categories/
Gas Safe Register — Commercial catering gas safety (catering engineer checks; record-keeping) — https://www.gassaferegister.co.uk/gas-safety/gas-appliances/commercial-catering/
WaterRegsUK — Backflow protection (five fluid categories; single check valve = category 2; double check valve = up to category 3; air gap = category 5) — https://www.waterregsuk.co.uk/topics/backflow-protection/
WaterRegsUK — RPZ (Type BA) valve (protection to fluid category 4; installation notified to the water undertaker; testing at least annually) — https://www.waterregsuk.co.uk/topics/rpz/
The Water Supply (Water Fittings) Regulations 1999, Schedule 2 (backflow prevention) — https://www.legislation.gov.uk/uksi/1999/1148/schedule/2/crossheading/backflow-prevention/made
HSE — Legionnaires’ disease: the control of legionella bacteria in water systems (Approved Code of Practice L8) — https://www.hse.gov.uk/pubns/books/l8.htm
Thames Water — Trade effluent (a consent is a legal document under the Water Industry Act 1991; discharging without consent is an offence) — https://www.thameswater.co.uk/wholesale/trade-effluent
Thames Water — Preventing blockages for food businesses (FOG discharge illegal; grease trap orderable under the Building Act 1984; local-authority inspection) — https://www.thameswater.co.uk/wholesale/best-practice-for-food-businesses
British Water / Grease Contractors Association — Grease Management Equipment Guide (BS EN 1825 grease separators recommended for new commercial kitchens; Part 1 design, Part 2 sizing, installation and maintenance) — https://cdn.ymaws.com/www.britishwater.co.uk/resource/resmgr/publications/codes_of_practice/gca_grease_management_equipm.pdf
Ealing Council Infrastructure Delivery Plan, Part One: Infrastructure Baseline Report, Feb 2024 (potable water supply split; controlled parking zones; River Brent main river and sewer-overflow flood risk) — https://www.ealing.gov.uk/download/downloads/id/19508/part_one_infrastructure_baseline_report.pdf
Landlord and Tenant Act 1985, Section 11 (residential repairing obligation) — https://www.legislation.gov.uk/ukpga/1985/70/section/11
Transport for London — Ultra Low Emission Zone — https://tfl.gov.uk/modes/driving/ultra-low-emission-zone

Commercial Plumbing in Ealing | Verified Commercial Plumbers