Each Spring we get calls about peoples sprinkler systems smelling! Let me explain…during the winter when you winterize your sprinkler system you are actually only draining water from the vacuum breaker. In a lot of homes there is still water left in the pipes. It’s been just sitting there stagnate for 4-6 months now and will develop a foul smell. When you turn your sprinkler system on for the first time it will start to flush all of this water out of the lines and also spread the bad smell. The good news is it will go away pretty quick. The bad news is if there was a lot of allege or dirt build up you may need to flush your lines out. Trash as fine as sand can cause your vales and heads to not function the right way and prevent the sprinkler system from spraying the lawn in the right way. The easy way to clean these line out would be to remove a nozzle on each zone and let the water flow freely until it becomes clean and clear.