Cabling a sewer is not something an inexperienced person should attempt. However, rental facilities and home improvement stores encourage people to venture into performing such task.
Questions you will want to ask yourself before you attempt to clear a blockage from your sewer line are:
- Are you on a septic system?
- Do you have a back water valve on your sewer line?
- Do you have a house trap on your sewer line?
- Do believe you have roots in your sewer line?
- Do you have a lift station in line with your sewer?
If you are on septic and not city sewer, you should first perform a visual inspection of your septic system to be sure your septic tank is sending effluent to the leach field. If not, put cabling your sewer on hold until you have an understanding as to why your septic system is failing. If you attempt to cable the main sewer line from inside the house, you must know if you remove the cleanout plug without caution, you could find yourself standing in a lot of sewage.
Running a cable downstream, toward a septic tank can cause you problems. For example if your send your cable too far out into the tank, the cable can get tangled in the tank. Chances of getting it out without having to go in the tank and retrieve it are slim. So, be careful as to how far out you allow your cable to travel. Most of the time, cabling a sewer line can be done from the tank to the house.
If you have a back water valve:
attempt to discover where the blockage is on the sewer line. The back water valve itself can hold debris and cause a blockage. If the blockage is in the back water valve, this takes patience and skill to relieve the blockage. Do not push a cable through the back water valve. Especially if there is no access to service the valve. You may not be able to retrieve the cable without excavating.
If you determine the blockage is downstream of the back water valve or in the back water valve, find an access point on that end and attempt to cable from there. A safe and effective method for relieving a blockage in the back water valve or down stream of it, is by using a sewer bladder. A sewer bladder is used to create positive pressure on the blockage. Attach a garden hose to a hose bib and the female threaded end of the sewer bladder to the male end of the hose. Insert the sewer bladder in to the pipe so that no part of the bladder protrudes over an opening or a branch fitting. The bladder expands with water pressure. If the bladder does not have equal pressure on all sides of the bladder, the bladder can over inflate and rupture.
Another tip in using a sewer bladder is, there should be no branch line downstream of the bladder. If there are branch fittings (meaning, drain lines pouring into the line you are working on), attempt to get the bladder past the branch fitting. Or, find an access point where you know there are no other openings for the pressurized water to be diverted to.
If you are pressurizing a sewer line, and there is an opening between the bladder and the blockage, the pressurized water will divert to the fixture that open drain line serves. You may still be able to clear the blockage with the head pressure you are creating. However, be careful because the water may overflow a sink or shower elsewhere.
Roots are another issue that can cause a cable to become stuck in the sewer line. Again, here is another opportunity to spend thousands of dollars having the line excavated.
If you have a lift station, your cable can get entwined with electrical cables, chains and rope all found in the holding tank of the lift station.
House traps present their own problems. If your sewer has a house trap also known as a main line trap, you should understand where to cable from, what direction the cable will travel and how to avoid having to put a lot of force on the cable. You don’t want to force the cable. Especially if the reason the cable is not going anywhere is due to the possibility of your cable sitting against a cleanout cover on the trap.