How to size a Septic Tank

According to BS6297 this is the formula: 

C= (180 P + 2,000)   

C is the size of the septic tank in litres.

P is the population to be served - this is potential not actual inhabitants.

(Formula assumes de-sludging on an annual basis, and children count as adults.)

So, you start off with 2000 litres and add 180 litres per person that could live in the property, not how many people actually live in the property.

Let's look at an example: 4 bedroom house maximum occupancy 6 = 2000 litres + 1080 (180 x 6) = 3080 litres would be the minimum size tank required.

At present the smallest septic tank size for a domestic property is 2700 litres.

if you require further information on getting the right sized tank please feel free to call us on:

0800 085 0640