GARDHACK TOOLS · WATER-SMART GROWING

Every drop has potential.

Turn your roof, local rainfall and garden size into a practical rainwater-harvesting estimate — with the assumptions visible.

Calculate your potential ← Back to Sustainability

PERSONALIZED ESTIMATE

Your water-smart calculator

Start with your location, then fine-tune the roof and garden inputs. All measurements are in US units.

Where you grow

US stateAnnual rainfall and water-rate figures are illustrative state-level inputs from the supplied calculator, not address-level measurements.

Roof footprint (sq ft)Use the horizontal roof catchment area.Garden size (sq ft)Used to estimate irrigation demand.

Your roof and storage

Roof material

Storage capacity (gallons)How much water your tanks hold at once.Water price ($ / 1,000 gal)Replace this default with your utility rate.

Estimated system cost ($)Used only for indicative simple payback; exclude or include installation as appropriate.

Estimate your usable share

Assumed capture utilization · 50%Scenario only: rainfall timing, storage, overflow and demand determine actual use.

YOUR WATER SNAPSHOTReady when you are

Good growing starts with good numbers.

Choose your state and calculate to see collection potential, practical water offset and storage context.

SMALL CHANGES · COMPOUNDING IMPACT

Use less. Grow more.

Rainwater collection works best alongside mulching, drip irrigation and right-sized beds. Calculations run in your browser. Email delivery depends on the availability of the GardHack email service.

Explore the GardHack approach ↗

Data note: state rainfall and water-price defaults come from the user-supplied prototype and have not been independently validated against current local records. Replace them with your local climate normals and utility tariff before making purchases. Runoff factors and 0.68 gal/sq ft/week are planning assumptions, not engineering design specifications. Rainwater-harvesting requirements vary by jurisdiction.