typical 150-300 per tanker visit
Advanced options
Off-mains drainage swaps the water company's sewerage charge (GBP 200-300/yr you're NOT paying) for emptying + maintenance: run properly, a septic tank costs about the same as mains sewerage: run badly, a failed drainage field is a GBP 5,000-15,000 rebuild. The one rule most owners learn expensively: the tank digests, the FIELD disposes: bleach-heavy cleaning, wet wipes, fat and "flushable" anything kill the digestion and clog the field: what goes down the drain is the maintenance schedule.
What The Septic Tank Calculator Works Out
- Annual running cost: for a septic tank, one tanker empty a year (1.5 for households over five) plus GBP 30 of minor upkeep and no power; for a treatment plant, the empty plus about GBP 120 of servicing and GBP 80 of electricity; for a cesspool, 6 or more tanker visits a year because it stores rather than treats. Emptying runs GBP 150-300 a visit depending on the area.
- The rules that bite: England's general binding rules bar septic tanks from discharging to a ditch or stream, and that clause surfaces in surveys and kills rural sales. Ask where it discharges before you offer, keep treatment-plant service receipts for buyers' solicitors, and check the devolved rules in Scotland, Wales and Northern Ireland.
- Keeping bills down: empty on schedule, book off-season, split call-outs with neighbours on the same lane, keep vehicles and trees off the field, and police what goes down the drain. Bleach-heavy cleaning, wet wipes and fat kill the digestion and clog the field; the bacteria sachets are mostly hope in a box.
- Minor upkeep, service and electricity (advanced): the simple mode hard-codes GBP 30 a year of upkeep for a septic tank and GBP 120 of servicing plus GBP 80 of electricity for a treatment plant. Override them with your own figures; service contracts run GBP 100-180 and a plant's blower draws GBP 60-120 a year.
- Mains sewerage charge you avoid (advanced): an off-mains household pays no sewerage element on its water bill, typically GBP 200-300 a year. The comparison card shows whether your system costs more or less than a mains household pays; run properly, a septic tank is about the same.
- Drainage field rebuild cost and life (advanced): a failed field is a GBP 5,000-15,000 rebuild with percolation tests and permits, and a well-treated field lasts 20-30 years. The reserve card spreads the rebuild over its life so the real annual cost of the system is visible; cesspools have no field and no reserve.
- All-in annual cost (advanced): the running cost plus the drainage field reserve, which is the honest figure to set against mains sewerage over the long run.
- Per person per year (advanced): the all-in cost divided by the household, for comparing a large household's higher emptying frequency with a smaller one's.