I thought that the dune lake sampling/monitoring was done on a monthly basis (http://sowal.com/coastal-dune-lakes-of-south-walton-county) as opposed to weekly. The beach water quality tests are done weekly. If that's the case, it may be misleading to say the lakes are fine unless they've done extra testing on the lakes, which I doubt.
However, if you take a look at the historical beach sampling results this is definitely unusual. For example, for both Grayton and Eastern Lake there are only a couple of moderate results in the last six years. No poors.
http://esetappsdoh.doh.state.fl.us/irm00beachwater/default.aspx
If you look at the other reports from Bay to Escambia counties, this is a wider spread issue than Walton County.
yes, i agree that it's wider spread than just walton county. that's what i said before. it doesn't look like septic tanks would be the issue since it's in pensacola as well, so like another poster said, i bet it is the flooding. i'm sure it will clear up and be back to normal soon. (although i don't really like the idea of the septic tanks being an issue! ick).
i too went back to the historical data after i posted this and was happy to find out that in the last 10 years, i don't think there has been an advisory at grayton! that's comforting and makes me feel like this is due to the flooding. TS Debby may or may not make matters worse though....