RainYard Tools
RainYard Tools

Stored rainwater

Cistern Size Calculator

Estimate a practical cistern size from roof yield and outdoor water demand.

Practical target735 galLimited by supply or dry-spell demand.
Monthly yield2,224 galRoof collection estimate.
Dry-spell demand735 galWater needed for selected days.
Quick ruleStorage should match both supply and demand.

Related

Next useful checks.

Rain Barrel Fill Calculator

See how much water a roof section can send to one or more rain barrels during a storm.

Roof Runoff Calculator

Convert roof area and rainfall into gallons and cubic feet of runoff.

Gutter Flow Calculator

Estimate gallons per minute coming from a roof during a rainfall intensity.

Downspout Count Calculator

Estimate how many downspouts are needed for a roof section at a chosen rainfall intensity.