Return your site to pre-development runoff with Promax’s Pre-Post Calculator
Attenuating stormwater runoff on complex sites can be challenging. Promax’s Pre-Post calculator will generate your own Stormwater Report quickly and efficiently, whilst sizing and locating the orifice at the same time.
Discover the ease of stormwater calculation with Promax. Simply fill out all the relevant data points below and print your stormwater report below. Note, if you need to find your rainfall data, get the HIRDS data here.
Please note the calculator will take a moment to load. Thanks for your patience.