YOUR WATER SUPPLY
Home rainwater tank
Illustration of your recorded level
● Comfortable buffer
14,400litres in your tank
Total capacity22,500 L
Protected reserve3,375 L
Daily use assumption430 L
Example tank · Add your first reading
A CLEARER PICTURE
Make every drop count.
A little insight today. More water security tomorrow.
Start with an example. These numbers are a demo until you add your tank.
Browser storage is unavailable. Changes are only held for this visit. Export your readings before leaving.
25days to reserve
At your current daily use, without more rain or a delivery.
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Planning estimate, not a guaranteed supply.Plan ahead, stay topped up.
Until your tank is empty33 days
No rain or deliveries assumed
Every 10 mm of rain could add1,600 litres
From your connected roof
Using 20% less could give you6 extra days
Before reaching your reserve
LOOKING AHEAD
No-rain estimate – – ReserveYour next 30 days
Based on your saved level, daily use and elapsed time.
✳
Your next good habit? A weekly tank check.
A fresh reading makes your water plan more useful.
How this rainwater tank planner works
Start with your tank capacity, measured level and estimated daily water use. Choose a reserve buffer and your supplier’s lead time. The dashboard estimates how many days remain above that reserve, while the scenario planner compares an assumed rain event and a possible delivery.
A 22,500 L tank at 64% holds 14,400 L. With a chosen 15% reserve and an assumed 430 L daily use, that leaves 11,025 L above reserve — about 25 full days without rain. Your numbers will differ.
Quick calculators for a single question
Calculate tank volume from dimensions · Calculate how long water will last · Estimate roof rainwater collection · Calculate a refill planning date
Does this use a weather forecast or a tank sensor?
No. Readings and rainfall scenarios are entered manually. Between readings, the estimate subtracts your assumed daily use. New rainfall is only included when you log a fresh measurement or test a scenario.
Are my readings saved?
Settings and readings save in this browser. There is no account, cloud sync or automatic transfer from another website. Export your readings before clearing browser data.
YOUR SCENARIO
A little rain can go a long way.
Before you book a delivery
Check the supplier’s lead time, minimum delivery, truck access and your available tank space. Order with a buffer; rain may not arrive.
A USEFUL LITTLE ROUTINE
Your level history
Readings are stored in this browser. Export a copy to keep your own record.
01 / PLAN
How long will your tank water last?
Turn a level reading into a useful planning window, with a reserve you choose.
02 / COLLECTWhat could your roof collect?
Understand the relationship between roof area, rainfall and collection efficiency.
03 / REFILLWhen should you arrange a refill?
Allow for delivery lead times, spare tank capacity and a dry spell.
Clear assumptions. More useful estimates.
Tankwise uses the figures you enter. Daily use stays constant in each scenario; actual use, leaks and rainfall can change your result. The reserve is a planning buffer you choose, not a prescribed safety level.
Collection estimate = rainfall in millimetres × connected roof area in square metres × collection efficiency. Storage is capped at your tank capacity. This planner does not assess water quality or certify a firefighting supply.