I work in biologically controlled water system. Peggy sells toilets.

Typical atmospheric air will contain 30,000 particles per sq. ft. with a
small percentage of Stochybotris Autra and various Aspergillis spores.
These are removed by filtration. There is NO place on earth where these
spores are not present. Most folks are tolerant of these species, some
are extremely reactive - hence cumulative dosage can be fatal for some.
Play the odds and risk the 'trots' or worse - your choice.
An independent 'collection' tank, then filtration into a (sanitized)
storage tank is the prime recommendation.

One must remember that until the western world corrected and
biologically controlled its water systems and methods .... the leading
cause of death and illness ...and probably the reason for low
life-expectancy was waterborne diseases before that change. The reason
for the low life expectancy in the 'third world' is STILL uncontrolled
water systems/sources. Simply draining rainwater into your boat's tank
is risky and quite archaic in light of modern practices .... and can be
quite dangerous. Even the 'ancients' who filled cisterns from rain
run-off used sand bed filters to purify and create a barrier from
biologically aggressive species while having absolutely NO idea about
such microorganisms. How soon we forget!


Peggy's 'bleach treatment' is a one-size-fits-all case and doesnt apply
to most stagnant (boat) water situations; plus, free chlorine in potable
water is a small risk carcinogen - take your choice.