There are a few main ways to go with solar water heating.
Passive Solar Water Heating
The first method is probably the one you’re familiar with. Basically you use some kind of dark container to heat the water in the sunlight, then generally use gravity to feed the water through a shower head and take your shower. This works great as long as you want a quick shower and you have lots of sunlight. If you feel like a shower after dark you’re just out of luck.
The gas method is probably the most popular way to get hot water. There are lots of simple setups sold that connect to a propane tank for heat and then give you a hot shower whenever you want it. This does rely on you having a supply of propane which you will need to refill and maintain.
The electric method uses an instant water heater to supply hot water. This is a great set up because you can use your solar power to heat the water and then you don’t need to burn fossil fuels, but you’re also not limited to daytime showering.
The hybrid method is very exciting because it combines the best of both the passive and electric worlds without the worst of fossil fuels.
This is a photo I took of one of the bath houses at Long Pine Key Campground inside Everglades National Park. As you can see from the roof, they are using solar water heating panels in addition to solar photovoltaic panels. This means they are able to store electricity in order to heat water when the sun is not out, or to make up the difference in temperature if there isn’t quite enough sun out.
Here is another photo I took at the Taos Earthship Community. It’s a little easier to see the different types of panels in this example. The big black one in the middle is just heating water, while the others are storing electricity.
This is a hugely advantageous system because they get the free hot water from the sun, but they also store up power to use in their electric hot water heater. This means that if the water coming out of the solar heater is not quite hot enough, then the electric system will make up the difference by pulling power from the batteries. What a clever system!