Most solar water heating systems (SDWHS) require very little annual maintenance.

"Closed Loop" SDHWS use an antifreeze solution that is circulated through the solar collectors and a heat exchanger at the solar storage tank. This heat transfer fluid must be checked occasionally to verify that the fluid is still in good condition. "Open Loop" systems often use water as the heat transfer fluid and it must be checked to verify that the fluid does not need to be "topped up". The glass on solar collectors should not require cleaning- the rain will do that. Each manufacturer identifies in their operating manuals the type and frequency of system maintenance required for their products. (CSA-F383 Standards requirement).

99.9% of SDHWS are installed as pre-heaters to existing water heaters. If the solar system stops working, or is working poorly, there may be no immediate or obvious indication of this fact. (Eventually you may notice that you're not saving money on your hot water bill!) For this reason it is a good idea to have some kind of monitoring equipment on the SDHWS, for example; thermometers on the line leading from the solar storage tank to the existing water heater, and and elapsed time meter on the solar loop pump (to record the number of hours the solar pump operates). These monitoring devices require that they be monitored if you are going to be able to determine if the system is working (or not).