While all water tanks need to be sealed, to screen out mosquitoes, the lack of proper filtering or closed loop systems will create breeding grounds for mosquito larvae. Our first filtering process, especially for the bigger in-house systems, starts at the gutters/downpipes already.
If the harvested rainwater is used for drinking, it MUST be filtered properly. Filtration, such as reverse osmosis or ultra-violet filtration will remove all pathogens. Reverse osmosis is energy hungry though and we prefer to use an alternative method. Other filtration consists of ozone and UV (ultra violet) treatment. Reports of illness associated with rainwater tanks are very infrequent. Rainwater is generally considered fit to drink if it smells, tastes and looks fine.
Certain paints and roofing materials may cause contamination. Lead-based paints for instance should never be used even as a primer onto metal surfaces. Tar-based coatings may affect the taste of the water as well. Chemically treated timbers and lead flashing should be excluded from roof catchments.
Maintenance of rainwater catchment areas includes regular removal of vegetation and debris from gutters. As long as a rainwater tank is kept closed to preclude light from entering, no algae will grow. The only maintenance that needs to be done is perhaps removal of the sediment on the floor of the tank once a year.
Another imperative is that rainwater tanks should have a pre-filter to prevent debris from entering the water tank/s and also to prevent any possibility of the feed pipe from a downpipe leading to the water tank from blocking. This pre-filter also prevents the ingress of mosquitos.
Apart from rooftops, tanks may also be set up to collect rainwater / storm water run-off from concrete patios, driveways and other surfaces. This water though may only be used for irrigation and toilet flushing, as it may be soiled from pedestrian and other animal use.
Rainwater Harvesting filtration:
Rainwater Harvesting has introduced a 5-stage filtration unit to compliment this system. All water, whether from a rainwater tank or stored municipal or on the municipal override will get filtered and sterilized to potable water. Maintenance / replacement cartridges are kept to a minimum; between two – three times a year, depending on the quality of the harvested rainwater.