I have a green plastic rain barrel and it came with a screened top to prevent mosquitos from breeding in the standing water. I use mine to water my flowers where the barrel is. There is not enough water and I cannot reach my veg. garden. Mine came with a hose conection near the bottom of the barrel.
I saw a new idea and it was a pump that allows you to use your "gray" water from your bath and sink to water your flowers with. I am thinking of loking into it if we have another summer like this one next year.