Cohesion is going to make almost all that water stay together, this work's on the same principal as those gutter's that only have a quarter inch opening in the front of the gutter, it does work. You will have few drop's escape but not enough to worry about. Use pea gravel underneath the catch basin's for leveling and drainage and you will never see water.
If you have to replace a catch basin, dig a big enough hole that you can pull that basin off of the pipe. This is where not using glue is big.
You can use silicon but it's not necessary and i wouldn't do it. Use duct tape to put everything together, but that's all it's for.
When you talk about 4" drain line's, they aren't airtight, if it's not sloppy loose, it's fine, "cohesion" is your friend.
A rubber coupling with clamp's is overkill, not to mention a unnecessary expense. I would use the speedi-drain's, they aren't that expensive. I have used a 4" 90* elbow with a round grate in a pinch.
As long as you have vented (airflow from one end of the drain to the other) your drain's and have at least a 2% fall over 10 feet, your drainage should work. Good luck.
Last edited by agrostis; 07-04-2013 at 01:03 PM.