Your post seems well thought out but to me if anyone would not eat fish from a lake with a sewage discharge but with no advisory due to the extremely small chance it could make you ill what exactly do you eat that there is a zero chance of any issue. There is chance of getting sick from anything we eat it is all over the news of issues in food prep and manufacturing causing lots of illnesses.

Each to his own but unless there is an advisory I would not hesitate to eat fish from any lake.

"Your post seems well thought out but to me if anyone would not eat fish from a lake with a sewage discharge but with no advisory due to the extremely small chance it could make you ill what exactly do you eat that there is a zero chance of any issue. There is chance of getting sick from anything we eat it is all over the news of issues in food prep and manufacturing causing lots of illnesses. Each to his own but unless there is an advisory I would not hesitate to eat fish from any lake. "

Here's my reason - As I said, the probability of getting sick from eating a fish that lives in a lake that has sewage discharge is small. But...when you know that contaminants can be present that you do not want in your stomach, you get to make a decision. YOU get to make that decision. MY decision is to go somewhere else.

Here is a real life example of MY decision. A friend of mine has a deer lease in a beautiful part of Texas, down near Menard. It is on the San Saba River. I used to go there in the off-season with him and fly fish the Lampasas. It's beautiful and the fishing is great. Then one day while we were driving around I noticed that the Menard wastewater is released up stream of the lease. I've never been back. Not only would I not eat the fish (which would be rare for me anyway), I do not want to wade in the water no matter how clear and beautiful it is. MY choice. Might not be YOUR choice.

What I presented was information so that you could make an informed decision, not necessarily for persuasion.

If I am not mistaken, isn't nearly all waste water discharged back into the creek systems?

It is indeed, every treatment plant has to discharge to the surface somewhere; and generally it is to a creek or river, though sometimes it is into a lake or the ocean. There are treatment plants that effluent directly into the Trinity River in the DFW area for instance. Some plants recycle water by piping it to golf courses and such, but not all of the effluent can go back recycled due to the overwhelming volume.

Most plants are measured by million gallons of water per day treated/discharged (MGD). Roughly speaking 10,000 people will generate One MGD of sewage. Most large cities have multiple sewage treatment locations that treat sewage from different areas of the city. Denton's Pecan Creek waste water treatment plant (WWTP) discharges 15 million gallons per day for instance. The Dallas south side WWTP releases 50 MGD into the Trinity. Fort Worth's Village Creek WWTP releases 166 MGD into the Trinity. No doubt there are more than just these two along the Trinity.

Additionally, storm water run-off from cities also drains into nearby waters. I doubt that there is any way to calculate how much water drains from streets and ditches in the DFW area into the Trinity River. Storm water can be particularly nasty since it is never treated at all. It picks up everything, every pollutant, every drop of oil spilled, every heavy metal, every pesticide, every herbicide, every illegally disposed of chemical, and carries it straight into the river. And it's not just when it rains that it drains - there's a zillion gallons of water being sprayed on lawns that runs down the curb to the drain system every day. Find the outfall pipe and you'll see a steady stream of water even during drought.

Personally I wouldn't put my big toe in the Trinity - but that's just me. Thousands of people play in the Trinity every year with no ill effects at all, right?

Smaller towns/cities generally have poorer process and control of the waste water process than large cities due to limited small town budgets. Bigger budgets mean better controls and processes, but they also mean larger volumes, so mistakes are bigger.

The questions are; how well is it treated, how far away is the release point, how many creeks, rivers, tributaries, and lakes between you and that outfall pipe.

Dilution is a very good thing. Dilution is King.

Interesting outtakes so far, as a banker I have been somewhat reluctant to keep fish form the banks lately, if I get a chance to get on a boat and get them from deeper cooler waters no hesitation, again it's all a matter of choice

This is not only a Lake Lewisville issue. Every lake around here (DFW) has pollutants in them to some degree as we do live in a city with over 7 million people in it. On the lakes that don't have an advisory, I also don't have any issues eating the fish from them.