Fats, oils, and grease (FOG) are the single largest cause of blocked drains and sewer failures in Kenya's urban drainage systems. That is why NEMA (National Environment Management Authority) and most county councils legally require all commercial food service operations to install and maintain a grease trap — and why inspectors specifically check for them during food business licence renewals.
The NEMA Requirement
Under the Environmental Management and Coordination Act and the Water Quality Regulations, commercial premises that discharge trade effluent (including kitchen wastewater) to the public sewer must treat that effluent to prescribed standards before discharge. For kitchens, this means intercepting FOG before it reaches the drainage system.
County environmental officers in Nairobi, Mombasa, Kisumu, and other major counties enforce this requirement during food business licence inspections and environmental audits. A grease trap that is installed but not maintained (filled beyond capacity) is treated the same as no grease trap at all.
Consequences of Non-Compliance
Operating without a compliant grease trap exposes your business to: fines issued by NEMA or the county environmental department; suspension of your food business operating licence pending installation of a compliant system; and in serious or repeat cases, forced closure of the premises.
Beyond the regulatory risk, grease entering the drainage system builds up in pipes, causing blockages that eventually require expensive emergency drain clearance — a cost that falls directly on the business whose effluent caused the blockage.
Types of Grease Traps
Counter-top grease traps sit on or beside the sink and intercept grease before water enters the drain. They are appropriate for very small operations — kiosks, small cafés, or food stalls — with a daily output of 20–50 covers. They require cleaning every 1–3 days and are not suitable for medium or high-volume operations.
Under-sink (inline) grease traps are installed directly in the drain line beneath the sink. They intercept FOG passively as wastewater flows through. Suitable for small-to-medium restaurants (up to approximately 80–100 covers per day), they require emptying every 1–2 weeks depending on the menu.
Underground grease interceptors are large-capacity units installed in-ground outside the building, handling the entire kitchen's wastewater output. Required for high-volume operations — restaurants serving 100+ covers per day, hotels, hospitals, schools, and institutions. They are pumped out by a licensed waste contractor typically every 1–4 weeks.
Sizing Your Grease Trap
The critical sizing variable is your daily wastewater flow rate — determined by your daily meal count, the volume of water used per meal, and the number of sinks discharging to the unit.
As a practical rule of thumb for Kenya's commercial kitchens: under-sink traps with 10–25 litre retention capacity suit operations of up to 50 covers per day; 50–100 litre units handle 50–100 covers per day; underground interceptors from 500 litres are required for 100+ covers per day. Hotel, hospital, and institutional kitchens typically require 1,000–3,000 litre interceptors.
Beyond Commercial Kitchen sizes all grease traps to NEMA guidelines based on your daily cover count. Contact us with your approximate daily meals and we will specify the correct unit.
Maintenance Is Non-Negotiable
A grease trap that is not cleaned regularly becomes a grease overflow point — the opposite of its purpose. The cleaning frequency depends on the trap size relative to your output: a correctly sized trap should be cleaned before it reaches 25% capacity with grease accumulation.
Keep a maintenance log showing cleaning dates and volumes removed. NEMA and county inspectors may request this log as part of a compliance audit. Contracted pumping services are available in all major Kenyan cities.
