On average, most homeowners pay around $380 for a septic pumping in London task. This amount can go as low as $190 and can go as high as $890 with the average cost falling under $280 to $520. The general cost of your septic pumping in London job will depend on the size of your septic tank and how many people are in your household. Pumping a smaller septic tank can cost around $100 to $200. On the other hand, pumping out larger septic tanks that can hold up to 1,500 to 2,000 gallons of water may cost $200 to $300. If you have a large household, it may affect the cost of your septic pumping in London because you may have to pump your septic pump more often.