Cleaning includes pumping it out completely, cleaning the walls and baffles, checking the inlet and outlet, and refilling it with water. Grease trap cleaning costs from €90.
How a grease separator works
A grease separator is a tank with baffles in which the flow of kitchen water slows down. Fats and oils are lighter than water and float to the surface, heavy food waste settles at the bottom, and water from the middle layer flows on to the sewer. For the separator to work, it must always be full of water.
The separator does not break grease down; it only collects it. When the layer gets thick, grease starts to flow out with the water, hardens in the pipes and causes blockages and smells, both in the building and in the street sewer.
Small and underground grease traps
| Type | Where | What to bear in mind |
|---|---|---|
| Under the sink | Cafés, small kitchens | Small volume: fills up quickly, needs frequent cleaning |
| Floor or basement separator | Restaurants, canteens | Needs clear access and ventilation |
| Underground separator outside | Large kitchens, food production plants | Cleaned with a vacuum tanker; vehicle access matters |
How often to clean a grease trap
The frequency depends on the separator's volume, the menu (fried food, chips, meat) and the number of portions. The manufacturer's instructions give a starting interval; in practice, after the first few cleanings you can see how quickly the grease layer builds up, and then a regular schedule is set.
- Water drains slowly from the kitchen sinks.
- There is a smell in the kitchen or near the hatch.
- The grease layer takes up a large part of the tank.
- The building manager or the water utility points out grease deposits in the sewer.
How grease trap cleaning works
- Scheduling We agree on a time when the kitchen is closed or quiet, so that pumping does not disrupt work.
- Pumping out With a vacuum tanker we pump out the entire contents of the tank: the grease layer, the water and the sediment.
- Cleaning We clean the walls, baffles and overflows where hardened grease has stuck.
- Inspection We check that the inlet and outlet are clear and that the lid seal is intact.
- Refilling We fill the separator with clean water so that it works straight away.
- Document We issue a cleaning certificate with the date and volume, which you can show to the building manager or during an inspection.
When pumping grease traps, we take the contents to a facility that accepts this kind of waste; it must not be poured into the domestic sewer.
Why grease must not get into the sewer
Riga's rules for using the mains sewer prohibit discharging wastewater that contains fats into the sewer, as well as food and production waste. A grease trap is how a kitchen meets this requirement, provided it is cleaned regularly.
Grease is harmful in buildings with a septic tank or a biological treatment plant too: it forms a thick crust in the septic tank, clogs the drain field and suppresses the bacteria in a BIO plant.
Riga City Council Binding Regulations No. 17 of 15.12.2017 “Binding Regulations on the Operation, Use and Protection of the Riga City Centralised Water Supply and Sewerage System”, sub-points 63.11.7 and 63.11.8, likumi.lv/ta/id/296134. Checked on 30 October 2026.
How to reduce the grease reaching the separator
- Scrape plates and pans into the bin before washing instead of rinsing them off in the sink.
- Collect used frying oil in a separate container and dispose of it as waste.
- Use strainers in the sinks so that food waste does not get into the separator.
- Do not pour large amounts of hot greasy water into the separator at once, because hot grease flows further on and hardens in the pipes.
The less grease reaches the separator, the less often it needs cleaning and the lower the chance that grease escapes into the sewer between cleanings.
How much grease trap cleaning costs
Grease trap cleaning costs from €90. The price depends on the separator's volume, the thickness and hardness of the grease layer, access (basement, indoors, narrow yard) and the distance outside Riga (~€1/km).
For a regular schedule or several sites: pumping services for businesses. All prices: prices.