You can certainly make a DIY solar water heater for your pool for $200 - give or take. It will be simple (and ugly) but you can do it. They will tell you to put together some pipes in a zigzag pattern and put them in a black box with a glass front. Like hot air, hot water rises, so if you put one end of the piping lower than the other, water will circulate and will be heated. They probably will recommend getting a solar powered pump to speed things along. The box will get hot and it will heat water, but you won't have much control over the process.

I would not try to make a DIY cheapo heater for your potable water though. If you need a diagram, you probably don't have the plumbing skills you need to be messing with your house. Even if you did, modern solar water heaters aren't just the simple tube designs. They have sensors and pumps and heat exchangers etc that keep the system operating properly.

Thank you, Bill. There are several sites that say it is easy and simple. My husband is an electrician and I just like to "know" things - not do the actual work.:)

I appreciate your detailed response and wish you well!