and I doubt there's actually any difference in 'potable' versus 'non-potable' water, since they both use the same water source, either the city, county, regional water system, or their own well....
with rare exception, and only if the dump station's water source is from a totally different system, such as a 'recycling/filtration' pump, or tank, the only 'difference' is actually that the 'non-potable' water outlet( the end of the hose itself ) can be susceptible to having potential contact with a sewer hose, or the dump area, where it could pick up a contaminant and thereby possibly transfer that into your water tank when you were to fill it... otherwise, it's the same 'water', whether it's cleaning out your hose, or filling your tank.
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