If you had other problems also,then a lack of vent pipe would cause the problem. It is probably not something yo can do yourself, because there may not have been any provision for installing one, and installing one improperly or in the wrong location will not cure your problem: i am on a septec system, and i have problems with my toliet all the time i had a plumber out and he said that i did not have a vent pipe, would that cause my toliet to not flush properly and if so can i fix it myself and if i can than how do i do it?