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FEATURE
Standards for plastic and
chemical storage tanks
The drought in parts of South Africa has encouraged people to
store rainwater and grey water, but few people know that water
must be stored and treated correctly to ensure that it is safe to use.
By Ina Opperman
supply by 2025, making better use of our water
resources through rainwater collection and enhanced
storage and management will become a critical part of
a more sustainable future,” says Wayne Wiid, chairman
of the Association of Rotational Moulders of Southern
Africa (ARMSA).
John Telford, managing director of Calcamite tanks,
agrees. “Even during a good rain season, South Africa’s
terrain is not ideal for capturing water and therefore
rainwater storage tanks are a smart way to ensure you
have extra water for your garden.”
Using grey water and rainwater can also save money on
water bills and irrigation. “We flush a lot of useful water
down the drain, which can be replaced by grey water. In
addition, the average household uses up to 40% of its
water for the garden, which can also be replaced by grey
water,” Telford says.
ARMSA
A bigger storage tank
for industrial use.
The recent publication of the South African National
Standard: SANS 1731:2017 for polyethylene (plastic)
chemical and water storage tanks, is the first step to
standardise the storing and treatment of rainwater
and grey water. Plumbing Africa asked experts and
industry players to explain what these standards are,
what they mean, and if they are enough.
Plastic water storage tanks are considered a better
choice for rainwater or grey water storage because they
are available in more sizes and can be used on any flat
terrain, while they are also light and therefore easy to
move. These tanks do not rust, and UV inhibitors are
added to the plastic during manufacturing to mitigate
degradation by sunlight. If a plastic tank is punctured, it
is also relatively easy to repair. “With experts predicting
that South Africa’s demand for water will exceed its
May 2018 Volume 24 I Number 3
However, it is not simply a question of installing a
tank and using the water. According to Vollie Brink, an
experienced wet services engineer, the plastic storage
tank is only one small element of rainwater and grey
water harvesting — the other elements needed to
complete a system that complies with health and safety
standards are most important.
“The National Building Regulations (NBR) determine the
standards for everything that is installed on a property.
While there is a new tank standard for plastic tanks,
there is no NBR standard for the use of rainwater or grey
water for domestic use, which is critically important. A
NBR standard for the use of grey water and rainwater
must still be developed and promulgated as regulations
in terms of the NBR Act,” says Brink.
Brink says some municipalities have drafted water by-
laws on the use of stored water, issued as guides for how
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