Septic & well cost calculators
Free, no-signup septic-system and private-water-well calculators for homeowners, buyers and rural property owners — septic system cost & installation, septic tank & drain-field sizing, pumping frequency & cost, well drilling & casing cost, well pump / pressure-tank / yield sizing, water softener & treatment cost, and well-vs-city budget & ROI. Every tool works on the prices you enter and shows its formula, a worked example and a reference table.
Septic System Cost
What a septic system costs on your line items and prices: a full new-system estimate, tank installation, replacement, drain-field replacement, cost by number of bedrooms, and a conventional vs aerobic vs mound comparison.
All Septic System Cost tools →Septic Sizing & Design
The septic sizing math: tank size by bedrooms & occupants, daily wastewater flow, drain-field absorption area, percolation-rate → soil-loading lookup, trench length & laterals, and tank capacity from dimensions.
All Septic Sizing & Design tools →Maintenance & Pumping
Keep the tank healthy: a pumping-frequency estimator, pumping cost by the gallon or a flat fee, inspection / riser / effluent-filter add-ons, and tank pump-out volume from dimensions.
All Maintenance & Pumping tools →Well Drilling & Cost
Budget a private well from the prices you enter: well drilling cost, a cost-per-foot normalizer, casing cost, a complete well water system builder, and a drilled vs driven vs dug comparison.
All Well Drilling & Cost tools →Well Pump, Pressure & Yield
Size the water side: required pump GPM / peak demand, total dynamic head & HP guide, pressure-tank sizing, a well yield / flow-rate test, daily household water use, and pump & tank replacement cost.
All Well Pump, Pressure & Yield tools →Water Treatment, Budget & ROI
Treatment and money: water softener sizing, salt usage & cost, whole-house filtration / UV cost, well-water test cost, a private-well vs city-water ROI, and a project budget allocator with a cost-per-gallon normalizer.
All Water Treatment, Budget & ROI tools →Septic System Cost
Septic Sizing & Design
Maintenance & Pumping
Well Drilling & Cost
Well Pump, Pressure & Yield
Water Treatment, Budget & ROI
Built for the whole rural-property water project — and to stay correct forever
SepticCalcs gathers the calculations homeowners, buyers and rural property owners reach for across a whole water project — septic system cost, septic & drain-field sizing, pumping, well drilling, well pump & pressure sizing, and water treatment plus budget & ROI — in one focused hub, in US units, without signup, with transparent formulas. Every tool shows not just the answer but the underlying formula, a worked example and a reference table.
Because the tools rest on timeless project math (tank gallons = L × W × liquid depth × 7.48; absorption area = design daily flow ÷ soil loading rate; trench length = area ÷ effective width; daily flow = occupants × gpd; pressure-tank drawdown = run-time × pump GPM ÷ acceptance factor; well yield GPM = gallons ÷ fill-seconds × 60; softener grains/day = hardness gpg × daily gallons; cost = quantity × your unit price) and stable conventions (7.48 gallons per cubic foot; ppm ÷ 17.1 = grains per gallon; psi × 2.31 = feet of head; tank-size-by-bedroom and perc → soil-loading planning bands), they stay correct with no maintenance — no material, drilling or service price list, no labor-rate database, no regional cost index, no live loan rate. Cost tools use the prices you enter from your own quotes and bills. More at Sources & formulas, Methodology and About. Planning foundation or basement work on the same property? That is a different job — see the sibling site BasementCalcs.
Estimates, not bids. Every cost result is a planning estimate — get itemized written quotes from licensed contractors; have septic design, drain-field sizing and well siting verified by a licensed septic designer or professional well driller and your local health department, and pull the required permits and inspections; test your well water with a certified lab before choosing treatment; the well-vs-city ROI is illustrative math on your figures, not financial advice. We make no water-safety or potability claims.