Frequently asked questions
- What is a raingarden?
- What is stormwater?
- Why should I build a raingarden?
- How big does my raingarden need to be?
- How much will it cost to build a raingarden?
- How long will it take to build a raingarden?
- Who can help me build my raingarden?
- Where do I buy the materials to build a raingarden?
- Are there different types of raingardens?
- What type of plants grow best in a raingarden?
- How many raingardens are there around Melbourne?
- What is water sensitive urban design (WSUD)?
- If I register my raingarden, where does this information go?
- How polluted is the runoff from my roof?
- Can I build a raingarden to filter greywater?
- Can I plant vegetables in my raingarden?
- Will my raingarden really make a difference?
1. What is a raingarden?
A raingarden is a water saving garden that is similar to a regular garden bed, but is designed specifically to capture stormwater from hard surfaces such as driveways, patios and roofs via downpipes after it rains. Planted with native shrubs and grasses, raingardens filter pollution and slow the rate of stormwater entering our rivers and creeks.
2. What is stormwater?
Stormwater is rainwater that has run off urban surfaces such as roofs, pavements, car parks, roads, gardens and vegetated open spaces.
3. Why should I build a raingarden?
Raingardens are good for you because they are water saving, especially if planted with native, drought tolerant plants. They are also good for the environment because they help clean and slow the rate of stormwater entering our rivers and creeks after heavy rain.
4. How big does my raingarden need to be?
If you are building a raingarden to catch the water runoff from your roof, then you need to determine the surface area of the roof. Generally a raingarden needs to be approximately 2% of the size of the runoff area. For example, if capturing runoff from a 100m2 area of roof, then your raingarden needs to measure 2m2. A raingarden sizing chart is included in our instruction sheets.
5. How much will it cost to build a raingarden?
For example, a planter box raingarden measuring 2m2, which can capture water from 100m2 area of roof, is likely to cost between $400 and $500 (plus the cost of a certified plumber). Prices will vary depending on the type of raingarden you build and the materials you choose. Please see individual instruction sheets for anticipated costs of building different types of raingardens.
6. How long will it take to build a raingarden?
This will depend on the size and type of raingarden you build. A small planter box raingarden is likely to take as little as a few hours, while an inground raingarden will take you longer because there is more work involved, like digging the actual raingarden bed.
7. Who can help me build my raingarden?
A good landscape gardener can design and build a raingarden that best suits your needs. If you want advice or assistance with building your raingarden from a qualified landscape gardener, you can contact Sustainable Gardening Australia. You will also need to employ a certified plumber to assist with any modifications made to your stormwater system.
8. Where do I buy the materials to build a raingarden?
Most good hardware stores have all the materials you need to build a raingarden. A full materials list, as well as plant recommendations, is included in our instruction sheets.
9. Are there different types of raingardens?
Yes, there are many different types of raingardens you can choose to build at home. Any of these raingardens can be registered on our website to be in the count towards our 10,000 raingardens target.
See: What is a raingarden? for a description of the different types of raingardens.
10. What types of plants grow best in a raingarden?
Although you can plant whatever you like, the best way to get the most out of your raingarden is to choose plants that donít need fertilisers or lots of water. Native Australian plants perform well in raingardens because they are used to long, dry periods, and can tolerate temporary wet periods. A full list of recommended raingarden plants is included in our instruction sheets.
11. How many raingardens are there around Melbourne?
The number of residential raingardens around Melbourne is increasing all the time, particularly since more raingarden information has become available though programs such as Melbourne Waterís 10,000 Raingardens Program. There is also a growing number of raingardens being built in public spaces as more local councils adopt water sensitive urban design (WSUD) to better manage stormwater.
12. What is water sensitive urban design (WSUD)?
Water sensitive urban design (WSUD) is a way of incorporating treatment of stormwater into urban environments. Raingardens, rainwater tanks, green roofs, swales, porous paving and infiltration raingardens are all examples of water sensitive urban design. The aim of water sensitive urban design is to help to replicate the natural water cycle, and contribute towards the more effective management of stormwater.
13. If I register my raingarden, where does this information go?
The information you provide when registering your raingarden is only used to help record our progress towards reaching the 10,000 raingardens target. Your information is kept confidential and is not used for marketing or any other purposes.
14. How polluted is the runoff from my roof?
Roof water, particularly in an urban environment, is known to contain a range of pollutants. Some of these include heavy metals (such as zinc, lead, copper and cadmium). Other pollutants include nitrogen, phosphorus and sediments such as dust, dirt and animal droppings. Many of these pollutants are harmful to human health and to our rivers and creeks.
15. Can I build a raingarden to filter greywater?
No you canít build a raingarden to filter greywater. Greywater (i.e. water from washing machines and dishwashers) is connected to the sewerage system and is not permitted to enter the stormwater system Ė even when filtered through a raingarden.
16. Can I plant vegetables in my raingarden?
Fruit and vegetables that need a lot of water or fertiliser to thrive are not suitable for raingardens. If you want to grow vegetables, a better raingarden design is to direct stormwater into the raingarden first, and then direct the filtered runoff from the raingarden into your vegetable garden. A good landscape architect will be able to advise you on the best raingarden design to suit your needs.
17. Will my raingarden really make a difference?
When built correctly, raingardens are an effective way to remove pollution and slow the rate of stormwater entering our rivers, creeks and bays. Our target of 10,000 raingardens across Melbourne will help to improve the health of Melbourneís rivers and creeks, but it is only the first step. Our ultimate goal is to see a raingarden in every backyard across Melbourne.