how do you consume a gallon of water ?
chugging a gallon of water will result in almost a gallon of piss.
water has to be "absorbed" by the body. herein lies the complications, most brought about by industrialism. Water needs to be of an alkaline pH for optimal absorption, acidified water (which is what almost all water is these days) is very difficult for your cells to absorb. dissolved particulate matter in most common municipal tap water also increases the inefficiency of water absorption. though one should still drink plenty of water in the form of just fluid water, fruits and veggies are becoming better sources for alkaline water than anything else in the modern era. if youre diet doesnt already include a large quantity of fresh, raw vegetables and fruits, you likely have more problems compounding each other than can be addressed singularly.
also, dark piss 100% of the time makes me wonder about your diet. does it include a lot of processed meats, pasteruized dairy, and prepacked/processed foods? lots of cooked conventionally produced foods? these will interfere with water absorption of course, but theyre also flooding your body with such a level of toxicity as to turn your urine that color.
just sit a glass of filtered water nearby wherever you are or whatever youre doing and consume it slowly over the course of an hour or so, then get another. dont consume water during or immediately after meals. after a meal has passed on from the stomach, resume filling your glass of water every hour or hour and a half. the more you chug, the less youll actually absorb.
(in addition, a heavily toxic diet will cause the colon to secrete a lot of mucus, which makes water absorption via the colon very difficult. alcohol increases this immensely).