Drinking water. So my body absorbs it?

I consume fiber husk powder to keep stools soft. My doctor has advised me to drink min 3ltrs of water every day to keep my stools soft. All these days, I have been gulping water as and when i remember. As a result, within few minutes of drinking water, i used to pee. Hence my stools were not getting soft enough. I realized this mistake, and from today, i have started drinking 250ml of water every 45 minutes. I have infact set a reminder to follow this schedule. Is this the correct way to drink water so it will be retained in the body for a longer time so my body absorbs it? I have also been drinking tender coconut and butter milk. Please guide if this is correct method. Also, please advise over this page instead of asking me to connect over a call.