About SepticCalcs
SepticCalcs is an independent project with one goal: to gather the everyday 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, free, no-signup hub with transparent formulas.
Who is behind it
Author and curator
To be clear about credentials: I am the author and curator of this site — not a licensed septic designer, professional well driller, geotechnical engineer, plumber or financial advisor. What I bring is relevant and real: building deterministic online calculators (open-source Python projects) and engineering training, i.e. rigor on the arithmetic and geometry. That is what it takes to curate a hub of calculators: transparent method, correct formulas, cited conventions and worked examples.
Our principle: transparent & durably correct
Every calculator shows its formula, a worked example and a reference table. The tools rest only on timeless project math (tank gallons = L × W × liquid depth × 7.48; absorption area = design flow ÷ soil loading rate; trench length = area ÷ effective width; pressure-tank drawdown = run-time × GPM ÷ acceptance factor; well yield = gallons ÷ fill-seconds × 60; softener grains/day = hardness × daily gallons; cost = quantity × your unit price) and stable conventions (7.48 gallons per cubic foot; ppm ÷ 17.1 = gpg; psi × 2.31 = ft of head; tank-size-by-bedroom and perc → soil-loading planning bands). There are deliberately no material, drilling or service prices, labor rates, regional cost indexes or live loan rates — cost tools use the prices you enter — so the results stay valid over time.
Correctness is checked against known reference values (see the methodology and the numeric self-check). The formulas and their basis are documented under Sources & formulas. All results are planning estimates: 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. Questions? Use the contact page.