The water you see in the 55 gallon garbage can to the left was collected in March of 2009 in a 300 gallon rain barrel shown below in the gallery.  On August 25, 2009 (5 months later)  it was pumped out of the 300 gallon barrel to use in the garden.  After 5 months the water is clear and the plants love it.  It cannot be used for drinking water as it has not been through sediment filters and a UV light, but it is excellent for irrigation.  Any dirt visible in the picture is on the inside of the garbage can which also is used to collect clippings for composting.  The collection barrels are on the north side of the home and don't get any sunlight.  The inside of the barrels are algae free and very clean!