DRAINS: Stormwater Drainage System design and analysis software for Australian practice.

Developed and supported locally in Australia, DRAINS allows users to design and analyse stormwater drainage systems, produce summary graphs and tables, and create pipe long-section drawings.

DRAINS incorporates the latest Australian Rainfall and Runoff (AR&R) guidelines.

  • Draw drainage system components such as sub-catchments, pits, pipes, detention basins, channels and overflow routes.
  • Use several available hydrological models recommended by the AR&R guidelines.
  • Solve the full unsteady flow equations in pipes, channels and overflow routes.

First software to incorporate AR&R Design Procedures & BOM 2016 IFDs (January 2017)


AR&R Compliant

First software to incorporate the new Australian Rainfall and Runoff (AR&R) design procedures.


Use IL-CL (the AR&R preferred model), Horton ILSAX, Rational & Extended Rational Method models, and a Storage Network Routing Module that includes RORB, RAFTS and WBNM.


Solve the full unsteady flow equations, which is useful for analysing complex surface flooding situations where storage or backwater effects occur in overflow routes, or when splitting surface flows in multiple directions.

Licensing Options

DRAINS is available as a perpetual licence in multiple versions.

All DRAINS licences include the Australian Rainfall and Runoffs’ (AR&R) Initial Loss – Continuing Loss (IL-CL) and Horton (ILSAX) hydrological models, and are capable of analysing AR&R temporal patterns and design procedures.

Note: When referred to below, a “link” is a pipe, channel, pump, orifice link or weir link.

Additional Modules

Three additional modules are available for DRAINS.

Storage Network Routing Module

The Storage Network Routing Module adds the RORB, RAFTS and WBNM storage routing hydrological models, useful when modelling large urban or rural sub-catchment areas where estimating the time of concentration with time area routing might be difficult.

DRAINS RAFTS does not rely on XP Rafts and is not affected by the discontinuation of XP Rafts by Innovyze.

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GIS Module

The GIS Module is useful where you need to interface with GIS systems that support ESRI shapefiles or Mapinfo MID/MIF files. This module allows transfer of data and results between DRAINS and GIS.

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Rational + Extended Rational Method Hydrological Module

The Rational + Extended Rational Method Hydrological Module adds the ability to model the rational method procedures with ARR87, ARR2019 and AS3500.3.

The Extended Rational Method allows users to produce hydrographs to improve detention basin analysis and utilise the full unsteady hydraulic model. This is achieved by including temporal patterns as part of the analysis and including the ability to model ensembles of storms from ARR2019.

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Updates & Support

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Workshops & E-Learning

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Recent News

December 10, 2020 in News

December 10th, 2020

We are receiving enquiries about the impact of Innovyze recently discontinuing XPRAFTS and how this will affect DRAINS RAFTS. RAFTS is one of many hydrological models available in DRAINS. Watercom…
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November 16, 2020 in News

November 16th, 2020

A new version of DRAINS is available that allows users to lock pit loss coefficient (Ku) values when revising coefficients, useful when modelling GPT devices. The former Premium hydraulic model has…
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August 21, 2020 in News

August 21st, 2020

A new version of DRAINS is available that improves multi-core processing.
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July 21, 2020 in News

July 21st, 2020

A new version of DRAINS is available that adds auto backup for some .drn files.
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For further information on our products, licensing options, updates, support and/or training, please get in touch.