Rainwater harvesting is a process of collecting and storing the rain that runs off from an impervious surface, in most cases a roof, so that it can be used at a later time for a number of tasks that require water. In the old days, the process of rainwater harvesting involved the placement of barrels or jars directly under parts of the roof or a number of downspouts, to be removed when full. These days, however, the process involves the installation of a multi-stage system composed of a catchment area, gutters, a downspout that is connected to the rainwater storage tank, and a pump. And since the collection system that’s used now is more complex, it follows that maintenance is also part of the rainwater harvesting process.
You’ll need to do more work to reap the benefits of this endeavor. But in exchange, you reap the following benefits:
* You get to use cleaner and safer rainwater for more tasks and more household chores that require water since the rain that falls on your roof can be filtered and treated several times so it’s safe for use in dish washing. Further filtration allows collected rainwater to become potable.
* Since rainwater is free, its collection and storage allow you to cut down on water expenses. The money saved can then be used for other needs.
* Gone are the days of worrying about your water provider being unable to provide you water for whatever reason, whether it’s because of maintenance on their end or because their source has depleted.
* Your plants grow healthier, since rain contains the right amounts of nutrients and minerals essential to plant life.
The Work that Needs to Be Done
* Getting the Components Together
The Catchment Area and Drain System:
- Many roof materials are already suited for rainwater collection, but it’s a different story when you plan to use collected rainwater for consumption—an unpainted metal roof or concrete is best for collecting rainwater for consumption.
- The larger the catchment area, the more rainwater collected.
- Although it’s true that concrete or unpainted metal roofs are perfect for collecting rainwater for consumption, gaining the most benefits from them requires that you clean them up from time to time. Rid them of dried leaves and twigs, plants, and vines, which can not only carry contaminants, but also attract animals like rodents and cats.
- Downpipe location helps you decide where a tank needs to be placed and how much of the roof can be connected with the tank.
- You can connect the roof to an underground tank to save space.
Roof Drainage and Tank:
- Rainwater that flows off the roof goes to downpipes that are distributed along the gutter. Downpipes can be one of three types:
1. Gravity System – Comprises at least one tank that’s distributed around a structure directly fed by downpipes.
- Typically, tanks are situated under a downpipe or at least near one.
- If you would like to connect many gravity-fed tanks in your system together, do so using below-ground pipes in order to regulate storage in all tanks.
2. Charged System – Usually set up to maximise catchment draining to one rainwater tank.
- Typically, pipes remain filled with water between heavy rains unless drained manually using something called a dewatering pit. It’s essential to drain charged pipes to prevent the buildup of both organic materials and stagnant water.
- Both arrangement and flow capability of charged systems needs to be assessed by experienced hydraulic engineers or plumbers to prevent the overflow of gutters during heavy rains.
3. Below Ground Tanks – Needs to be sealed properly to prevent ground water inflow.
- Needs to be sited in order to allow the draining of all down pipes into the tank. Do this by ensuring that tank overflow is 50mm below tank roof inlet.
Selecting Your Tank:
Tanks come in a wide array of shapes, materials, and capacities. To choose one that best suits your needs, you may need some assistance from a supplier of rain water tanks in Sydney.
The ideal filtration system for a rainwater collection system is composed of the following:
- Downpipe and Gutter screens: Screening devices that are positioned between tank and roof surfaces help separate debris from rainwater. A combination of fine and coarse mesh screens may be set up in order to remove various debris and prevent pest access to the tank.
- Inlet and Tank screening: Usually, fine and coarse mesh screens are set on the water tank roof to filter rain at inlets. On the other hand, finer screens are set over tank outlets to prevent access by mosquitoes. Another type of inlet screening that should be installed is a sun screen, which minimises the penetration of light into your tank to prevent algae buildup inside.
- First Flush Diverter: It’s important to have a first flush diverter set up before the inlet and after the screening devices on downpipes, since this device is a safeguard against dissolved contaminants and fine particles.
An in-ground diverter is another option that’s ideal for all sloping sites. This is able to support charged pipe drainage.
- Passive Treatment: It’s a type of treatment that’s intended for the inside the tank, and is done because of sediment settling and biofilm formation on the interior tank walls. One way of doing this is dewatering the tank after every few years or so.
- How Outlet Height Helps Keep the System Clean – A 100mm outlet height reduces the chances of sediment re-suspension, thus helping to reduce the chances of sediment suction into your water supply.
Selecting the Pump:
There is only one rule to follow when it comes to selecting a pump for your rainwater harvesting and storage system: Select a pump that allows collected rainwater to be evenly distributed across your residential plumbing system.
* Maintenance Work
Ensuring the safety and potability of collected rainwater requires that you the following maintenance steps:
- Maintain the cleanliness of your roof
- Maintain the cleanliness of outlet and inlet screens to prevent the entry of pests and contaminants
- Desludging the tank once every three years
- Regular checking of mains control switch and pump to ensure that they are working
- Repair of every leak so the pump does not go through cyclic starts and stops.