Page 28 - Build 151

PRECAUTIONS AND MAINTENANCE TO KEEP RAINWATER COLLECTED FROM ROOFS SAFE TO DRINK
BUILD
Collecting drinking water from roofs
Collecting rainwater for drinking can be practical, money saving and sometimes necessary. For safety’s sake, though, it’s important to have the correct set-up that is regularly maintained.
RIGHT
BY ALIDE ELKINK,
FREELANCE TECHNICAL WRITER, WELLINGTON
AN ESTIMATED 10% of New Zealanders obtain their drinking water from rainwater collected from the roof.
If roof-collected water is clear and has little taste or smell, it is generally safe to drink.
To ensure it is safe and does not become contaminated, precautions are needed and the system and storage tank regularly checked, cleaned and maintained.
Be aware of contamination sources
The two types of contamination hazard are microbial or chemical. Microbial contamination is caused by faeces from birds, animals and insects, from dead birds and animals and decaying organic matter and when underground storage tanks are not sealed or protected from ground run-o .
Chemical contamination comes from pesticides and spray drift, ue or chimney emissions, paint or other roof coatings, roo ng materials such as lead ashings and tra c and industrial emissions.
Sediment will accumulate at the bottom of the tank and may contain high concentrations of chemicals.
Take precautions to avoid contamination
To minimise the risk of rainwater contamination:
● ensure the roof surface is suitable for collecting
potable water
● keep the roof clean and free of debris
● keep the roof catchment area clear of
overhanging branches and therefore away
from birds, rodents, possums and cats
● avoid installing a television aerial or other
xtures that may provide roosting for birds on the roof
roof collection area
26 —BDueicledm1b3e9r —20D1e5/cJeamnubaery22001316/J—anBuuarilyd2015141
Figure 1
roo ng
Leaf guard for gutters.
rainwater head with sloping perforated screen
Figure 2
gutter
leaves and large debris are screened out
rainwater downpipe to rst- ush diverter and storage tank
Leaf screen tted to downpipe.
gutter
expanded metal leaf guard