high-density polyethylene (HDPE),
polyethylene terephthalate (PET), and
cross-linked polyethylene (PEX), or
thermoplastic polymer, which have well-
known health risks for end users. These
chemicals start mixing with water when
used for a long time and when these
reservoirs are washed with detergents.
Leaching also happens when
these are exposed to UV rays and
high temperatures, as well as from
natural breakdown. When these plastic
tanks are exposed to intense heat,
especially in the long summer months
when the mercury rises above 40°C in
some countries, the chemicals start to
break down and mix with water. These
plastics are also known to alter the
physical properties of water, despite
the manufacturers’ claims that these
alterations dissipate with time.
The dissolved chemicals, when
ingested by people through drinking
water, have many known side-effects
on the human body. For instance,
BPA severely affects the endocrine
system and is also known to cause
cancer, asthma, cardiac problems,
and reproductive system irregularities
in women. Owing to these problems,
many developed countries have banned
the use of plastic tanks for drinking
Plastic tanks used for rainwater harvesting.