Tank Size Calculator

Step 1 - Check how much rainfall there is in your area

Or for a more specific figure, visit the Met Office website.

Step 2 - Enter your collection area

The collection area is just the footprint of your property (we deal with the roof pitch later)

Please enter your dimensions below:

Step 3 - Roof Pitch

The roof pitch has a bearing on how much water runs off and how much goes down the downpipes.

Refer to the chart below and enter your "Drainage Co-efficient" as appropriate.

Step 4 - Filter Efficiency

Filters do not always give 100% water yield. Ones that self clean often loose between 5-10%

Unless you know otherwise please leave the box below as 95%

Your Tank Size Recommendation

Once you have completed the entire form, click the button below to calculate your recommended tank size