7 Kin Homestead
7 KIN HOMESTEAD

RAINWATER CATCHMENT CALCULATOR

Tell me where you live and what you're running. I'll show you exactly how much water your roof can catch, whether it's enough, how big your tank needs to be, and what your state says about all of it.

01
Your Roof & Rainfall
02
How Much You Use
03
Garden & Animals
04
Your Full Picture
7 Kin Homestead
7 KIN HOMESTEAD
Rainwater Catchment Calculator

📍 Where Are You & What's Your Roof?

ZIP code pulls your real monthly rainfall — not a national average. Your roof is your collection surface. Bigger roof + metal = more water. Simple math, big difference.

Your ZIP Code
Roof Catchment Area
sq ft
Use the footprint of your roof — roughly the same as your home's square footage.
Roof Material
🏗️ Metal
90% efficiency
🏠 Asphalt Shingle
80% efficiency
🏛️ Clay / Tile
75% efficiency
🌿 Green Roof
40% efficiency
First-Flush Diverter?
I have / plan to install one
Diverts the first dirty runoff. Reduces yield ~5% but greatly improves water quality.
How Many Dry Days Can You Ride Out?
30 days 45 days 60 days 90 days
How long your tank holds you over with zero rain. Desert climates need 60–90. Most of the US is fine at 30–45.

🏡 How Much Water Do You Actually Use?

Be honest here — the more accurate this is, the more useful your results. Toggle off anything you won't be running on rainwater. Most off-grid folks start with 5–15 gallons per person per day.

People in Household
people
Gallons per person per day — be honest
Daily use per person
10 gal/person/day
1 gal
Extreme conservation 25 gal
Off-grid typical 100 gal
Comfort / standard
What will this water actually do?
🚿 Showers & Bathing
🚽 Toilet Flushing
🍳 Cooking & Drinking
👕 Laundry
🍽️ Dishwashing
Outdoor Use
🚗 Vehicle washing
🌲 Yard / landscaping

🌱 Garden & Animals — the Part People Forget

This is where most homesteaders undersize their system. Your goats and garden can drink as much as your house. Add everything — I'll calculate peak-season demand so your tank doesn't run dry in August.

Garden / Growing Area
sq ft
Raised beds, market garden, orchard area. Leave blank if none.
💡 Garden demand is calculated seasonally — only irrigation months count, and in-season rainfall automatically offsets your need.
Garden Water Intensity
Low
Dry-climate crops Medium
Mixed vegetables High
Water-heavy crops
Livestock — tap to add, set quantity
🐓
Chickens
0.5 gal/bird/day
🦆
Ducks
1 gal/bird/day
🐐
Goats
2 gal/head/day
🐷
Pigs
4 gal/head/day
🐑
Sheep
2 gal/head/day
🐄
Cattle
30 gal/head/day
🐴
Horses
12 gal/head/day
🐇
Rabbits
0.25 gal/head/day
Additional Factors
🐠 Aquaponics / Fish pond
🌡️ Hot & dry climate (+20%)
💧

Your Water Picture Awaits

Work through the three steps on the left, then hit Calculate on the last step to see your full rainwater system breakdown.