Not that my current round took off but in my last three grows, I found 2 gallons of water is what it takes to completely drench a 7 gal pot. I do get a little run off (or leftovers), but not much. At least 1.5 gallons stays in each 7 gal pot. I use 1/2 gal water to do two 1 gal pots and always need a little extra to drench them completely. My rule is 1:4 water to soil.