Well: Off-Grid Water Calc

Well is an off-grid water-system sizing calculator and log for homesteaders, rural property owners, and households on private wells, cisterns, or rainwater catchment. Every threshold, every dose, every sizing recommendation cites a named source — Penn State Extension, USDA NRCS, ARCSA, Texas A&M AgriLife, EPA, USGS, NSF/ANSI 55.

The Safe Drinking Water Act doesn't regulate private wells. 23 million US households are on their own. Well makes the official guidance readable, calculable, and tied to your specific system.

WHAT WELL DOES

• Rainwater harvest — Roof area × annual rainfall × material runoff coefficient. Metal 0.95, tile 0.90, asphalt 0.80, green 0.30 per Texas A&M AgriLife. Optional first-flush per ARCSA 63-2020.

• Tank and cistern volume — Vertical cylinder, horizontal cylinder, rectangular. Plus the 10–15% freeboard rule for real working volume.

• Cistern sizing for demand — Household × per-person daily use × buffer days (3, 7, 14, 30) → required gallons. Recommended Norwesco HDPE preset.

• Pump sizing — Bathrooms → peak GPM. TDH = pumping level + above-ground rise + delivery pressure × 2.31 + 5% friction. HP recommendation against Goulds GS (Xylem) or Franklin Electric FS / FPS / 3200 curve range. Per USDA NRCS 210-NEH Parts 631 + 650 Ch 12.

• Pressure tank drawdown — Amtrol Well-X-Trol WX-201 / -202 / -203 / -255 / -302 drawdown at 30/50, 40/60, 50/70 PSI. Motor-protection pump-cycle target.

• Well drawdown + recovery — Pumping test math. Static vs pumping water level, specific capacity, sustainable yield, recovery time. Per USDA NRCS CPS 642.

• UV dose — NSF/ANSI 55 Class A (40 mJ/cm² anti-pathogenic) vs Class B (16 mJ/cm² supplemental). Viqua VH150 / VH200 / VH410 sizing. Pre-filter check (hardness > 7 grains/gal or iron > 0.3 mg/L). 9,000-hour lamp schedule.

• Filtration stages — Ordered recommender from your water-test inputs: sediment → iron/manganese → softener → arsenic → carbon → UV. Softener sized in grains by household × hardness × 5-day regen cycle. Arsenic flagged at 0.005 mg/L (recommended) and 0.010 mg/L (EPA MCL).

• ARCSA checklist — 16-item compliance checklist per ARCSA/ASPE/ANSI 63-2020 covering catchment, conveyance, tank entry, treatment, distribution, backflow prevention.

MULTI-ENTITY HISTORY

Save unlimited water systems with components (well, pump, pressure tank, storage, UV, filter, softener, RO), water-test results with EPA MCL badges (green / yellow / red), and recurring maintenance reminders (UV lamp 365 d, pre-filter quarterly, pressure-tank precharge annually). SwiftUI Charts trend per analyte.

PERMANENTLY FREE

Safety-critical reference stays free, always:

• EPA MCL reference — arsenic, nitrate, lead, coliform, uranium
• Rainwater laws by US state — 50 + DC with statute citations (CO HB 16-1005, UT §73-3-1.5, CA SB 1422, TX Tax Code §151.355)
• Testing cadence — per Penn State Master Well Owner Network
• Citations & Sources with URLs
• Water-test result MCL badges — existing logged results stay visible

48-HOUR TRIAL, THEN $9.99 ONE-TIME

Every calculator, every brand preset, every paid feature unlocks for the first 48 hours after install. After the trial, $9.99 unlocks Well Pro for life. No subscription. No ads. No analytics. No data collection. Family Sharing not enabled.

NOT WHAT WELL IS

• Not a medical or water-quality testing device. MCL badges read against your reported lab results — they don't measure water.
• Not a state-licensed driller log.
• Not an AI advisor. Every recommendation is rule-based against a named-source range.

Made by Moon Dog. Pay once, no subscriptions.