Cost guides
What off-mains drainage work actually costs, and what makes one quote differ from another. Written to tell you whether a price you have been given is in the normal range, and what to ask if it is not.
Ranges, not quotes
These are typical market ranges for domestic systems in this part of the country, not quotes, and not prices this site can offer. They are gathered from generally published UK contractor price guidance and are intended to tell you whether a quote you receive is in the normal range. Real prices vary widely with access, ground conditions and how far a tanker or a digger has to travel. Anyone quoting you from a phone call alone, without seeing the site, is guessing.
Ranges last reviewed July 2026.
Septic tank emptying cost
What a septic tank empty typically costs, what drives the variation, and how to tell whether a quote is fair.
Read the guide →Septic tank replacement cost
What replacing a septic tank typically costs, why the drainage field usually decides the figure, and what a fair quote itemises.
Read the guide →Sewage treatment plant cost
What a package sewage treatment plant costs to buy, install and run, including the ongoing costs a septic tank does not have.
Read the guide →Soakaway cost, and when you need one
What a drainage field or soakaway costs, when the rules require one, and why a percolation test comes before any price.
Read the guide →If you are trying to work out what your system needs before you think about cost at all, the guide to the General Binding Rules explains what the law actually requires of an off-mains property.
Not sure which of these applies to you?
Describe the problem and we will tell you what you are most likely dealing with, and put you in touch with a local specialist where one covers your area. No charge for that, and no obligation.