Price guidance from a published UK cost guide (MyJobQuote, September 2026). Regulatory points checked against GOV.UK, October 2026.
What it typically costs
One published UK price guide from September 2026 puts a routine empty at roughly £90 to £130 for a small 4,500 litre single-chamber tank, rising to around £260 to £300 for a large 17,500 litre multi-chamber tank. Those are national figures for straightforward jobs. Rural access, a long hose run or an overdue tank can all push the price up, and emergency call-outs cost more than a booked visit.
What moves the price
Tank size and type. The more the tank holds, the more the tanker has to take away. Cesspools hold everything and fill quickly, so they cost more over a year even if each visit is similar.
How full and how overdue it is. A tank that hasn't been emptied for years can have a thick, compacted layer of sludge that takes longer to break up and remove.
Access and hose distance. Tankers need to park within hose reach of the tank. Long runs, narrow lanes, gateways, slopes and soft ground all add time.
Covers. Buried, seized or hidden covers have to be found and lifted before any work starts.
Urgency. A planned empty is cheaper than an emergency visit for a tank that's overflowing or backing up.
How often you'll pay it
The general binding rules say the sludge must be removed at least once a year, or in line with the manufacturer's instructions. For most households that means one empty a year. Bigger households, small tanks and busy holiday lets may need more.
How to keep the cost down
Keep the covers clear and visible, and tell whoever's booking the job where the tank is and how close a tanker can park. Book before the tank is overdue rather than waiting for a problem. Avoid putting wipes, fats and chemicals down the drains, because they shorten the time between empties and can damage the drainage field.
When emptying isn't the fix
If the tank fills much faster than it used to, or the garden stays wet after an empty, the problem is usually the outlet or the drainage field. Emptying more often only treats the symptom. That's the point to have the whole system looked at.
Who can empty it
The waste must be taken away by a registered waste carrier. You can check a company on the Environment Agency's public register of waste carriers before you book.
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