Service calls around this time of year should be book soon, especially if you are looking to have your annual maintenance or tune-up completed for your Air Conditioning unit.
Even more importantly is having your plumbing throughout your entire home checked too, and on an annual basis. It helps for avoiding any possible flood risks and it helps prevent any embarrassing toilet overflows when hosting your summer patio parties.
1> Have your mainline serviced - Clogs from flushed objects or tree roots can cause havoc on your home's drainage. Mainline work can be as simple as a couple hours work, depending on the severity of debris and other in your line. Something you can easily do on your own is to clean all U-joints under all your sinks.
2> Ensure that a sump pump / pit and backwater valve are installed in your basement. If you don't we can't emphasize enough how important these are, especially if you're in a flood-prone area of the city. If you already have these installed, it is just as important to annually maintain it so it works when you need it to.