I used to own a landscape company that did a TON of drainage work. New developments are infamous for grading just enough to pass muster, but once everything settles... well, you already know!

Here's my advice, take it or leave it - happy to answer any other questions you might have:

The main issue is elevation - Baton Rouge is flat, and gravity is the best way to move water - so unless the lot is built up, there isn't anywhere for the water to go. We also have dense clay soil and a lot of rainfall, so the ground doesn't soak up much, and French Drains don't really work here. If you have a contractor try to sell them to you, ask for a client reference that has had them installed 3-5+ years ago. It's possible that someone is making it work, but I have yet to see it happen.

There are two systems that people call "french drains" - one is basically an underground holding tank filled with gravel that holds the water until it soaks into the surrounding area (which it won't, because of the clay soil and large amount of rainfall). The second (more common) has an "outflow" - same idea, but shallower trench, filled with gravel (and maybe perforated pipe) that moves water via gravity to a lower point. If you have the fall/elevation to do #2, you're 100% better off using solid pipe and catch basins.

Long story short, the only sure fire way to get rid of standing water in your yard is to install catch basins (plastic or concrete drain box with a plastic or metal grate on top) connected to solid pipe that extends out to the street. I always recommend solid pipe over corrugated/flexible pipe - I've dug dozens of corrugated pipe systems up and replaced them. The additional cost is worth it to do it once and be done- if it gets clogged, you can snake it out... if corrugated pipe or a french drain gets clogged, you have to dig it up and start over. You need approximately 1/8" of fall per linear foot of drain pipe, so if it's 100 feet from your back yard to the street, you need 1 foot of elevation. If your property is flat, and a contractor says they can make it work, make sure they're using a laser level (like you see surveyors use on a tripod). You may need to do some grading to get water to move to the catch basins, but assuming your yard is fairly level, it probably won't be much. Pro-tip: get gutters (if you don't already) and put catch basins under the downspouts.