How many trailers can you hook to only one 4" pvc line?


Rerouting some defective sewer pipe to go straight into city sewer. The run is about 225 feet and I am replacing with 4" pvc. I am in the county so there are no regulations. How many trailers can I put on the 4" schedule 40 PVC before I have to run a second line? I would like to have only one sewer tap. Can it handle 6 trailers and 8 RV’s on one 4 inch PVC sewer run with plenty of fall? What are you running in your parks?

Thank you,



See above link 4" at 2% slope max gpm is 50. Figure max flow of 10 gpm per unit gives you a theoretical number of units of 5. However I would never run more than 2 or 3 units on 4" as a short service lateral to a main. In your case go with 6" Sdr 26 not 3034 pvc pipe. 6" is really the minimum for a gravity sewer main in most people mind.