Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>
6.3 Stormwater reuse
Stormwater is generally of a higher water quality than wastewater. Reuse (or
strictly 'use' of stormwater can take place at two levels (household and municipal)
or even at a larger (regional) scale if desired. Use at the household and municipal
levels is described below.
6.3.1 Household level

Figure 2.45: Diverter for the first flush from roof run-off
Householders can use stormwater by collecting roof run-off in a tank for
use as drinking water (common in arid regions), flushing toilets or for
irrigation of the garden. The first flush of roof run-off can be contaminated
by dust particles, leaf litter and animal droppings. The first flush can be
simply diverted using a simple diverter (Figure 2.45). A screen can be placed
at the inlet to the tank to filter gross particles. Water for drinking will
still need to be boiled to denature pathogens.
Water from the roof can be directed to the garden beds directly rather than
through soakways, and in this way shallow rooted vegetation can benefit from
the water, especially in arid regions.
6.3.2 Municipal level
At the municipal level stormwater can be stored in ponds for use for
irrigation of parks and gardens and for fire-fighting purposes. This is in
addition to employing the ponds for flood control and for improving the
amenity value of the water as described in Section 2 (4.3). Other uses are for
groundwater recharge, either as a means of storing water, e.g. during the
rainy season, for withdrawal in the dry season. Groundwater recharge can also
be used to prevent encroachment of sea water near the coast where there is
heavy groundwater withdrawal in excess of natural replenishment by
precipitation.
Stormwater collected from community buildings (i.e. government and
churches) may be stored in reservoirs to be used by the community during dry
periods. This method is used in the Pacific SIDS atoll countries of Tuvalu and
Kiribati.
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