In the summer, the Gulf of Mexico water temperatures can reach into the 90s. This warm water can harbor dangerous levels of bacteria especially when mixed with the nutrients from water runoff.
It is a good practice to check the bacteria levels before heading to the beach. For Florida beaches you can check the website http://www.floridahealth.gov/ and search for “Florida Healthy Beaches Program”. You then chose the county and find the beach you are intending to go to (They do not list counts for Hernando County).
You can see whether the last bacteria count was “Good” and if there is an advisory on the beach. You can also look at the the recent counts on that beach and nearby beaches.
It is unfortunate to drive to a beach only to find out that you should not swim, because of high bacteria counts. This resource lets you know ahead of time how healthy the beach was during its last check.