Clogged Drainage or Irrigation Pipes

Q. I have a drainage pipe for my landscape that is clogged.  I tried running a “snake” through it to clean it out, but it wasn’t able to do the job.  Any suggestions?

A. I had a similar problem recently, it was with a sewer rather than a drain pipe, but the solutions are similar.  My sewers backed up, after trying my short snake and getting nowhere with it I realized it was a major blockage and called a sewer cleaning company.Over the years I have come across a lot of clogged pipes in landscapes.  They tend to fall into to categories when it comes to cleaning them out.

Dirt or Debris in the Pipe

When my sewer line backed up I called a sewer cleaning company and they came out and tried to snake it using a metal power snake.  A snake is typically the first thing they try, it’s cheaper due to the low cost of the equipment they use, but it doesn’t really do a very good job as I discovered.  In my case the standard metal snake would not budge the clog and the snake wound up all twisted up and jammed in the pipe.  It took the poor guy a long time to get it out!  So they moved up to using a hydraulic cleaning tool (aka hydro-jet, hydraulic flusher, hydro-scrub, etc.)  This tool uses extreme high pressure water from a pump that is blasted through several tiny nozzles on the end of a PEX tube.  The hydraulic cleaner blasted right though the blockage, plus it really cleaned out the pipe.  It costs more than snaking, but it works great.  My sewer has a clean-out opening near the street which allowed my to get a look into the pipe before and after the cleaning.  After snaking the line using the metal snake there was still a lot of stuff that had built up stuck to the inside of the pipe.  After the hydraulic cleaning it was almost completely clean inside.  Pretty amazing, I was so impressed I decided to have the guy clean all my sewer pipes with it as a preventive measure.  I would never go back to using a snake, next time I’ll just have them start with the hydraulic cleaner.  The high pressure water just cuts through stuff.  So if your blockage is caused by dirt and debris that has collected in the pipe, you can start with snaking it (you can rent a snake if you want to try it yourself.)  If you have someone clean it for you I would just skip snaking it and have it hydraulic cleaned.  Hiring a pro to snaking a pipe is generally about $50-100 USD, the hydraulic cleaning runs $150-200 USD.  Costs are year 2013 for the Southern California area.

Tree Roots and Crushed Pipes

Sadly, my experience is that often a pipe that does  not drain is not a blockage that can be removed with either a snake or a hydraulic cleaner.  It is caused by tree roots actually crushing the pipe.  If you have big trees in the vicinity of the pipe, this is likely the cause.

What happens is a trees roots create a “Y” where one root goes over the pipe while another passes under it.  As the tree roots grow and increase in diameter they squeeze the pipe, they can exert an amazing amount of force!  (You’ve probably seen places where tree roots have lifted concrete curbs and sidewalks, so you have seen for yourself how much force a root  can exert.)  If it is a plastic pipe they will squeeze it until it is flattened and no water can get through.  I have seen this many times with PVC irrigation pipes and even with ABS sewer pipes.  The corrugated poly drainage pipe often used for landscape drainage pipes, roof drains and sump pumps is very easily crushed.  Unfortunately a drain cleaning tool like a snake or hydraulic cleaner can’t fix a crushed pipe.  If you know where the pipe runs through the landscape you can use a “fish tape” to find out where the blockage is.  if the pipe has an open end you feed the tape in there.  If not, yuo may need to cut a section of the pipe out to insert the tape.   Just feed the tape into the pipe until it hits the blockage.  Now mark the location on the tape where it hit the blockage.  Pull the tape out of the pipe and lay it along the known pipe route on top of the ground, with the location you marked at the point you inserted the fish into the pipe.  The end of the tape should be in about the same location as the blockage.  Dig up the pipe and you will very likely find a bunch of roots and a flattened pipe.  Cut out the roots and the bad pipe and replace it.  If the roots are large you may need to relocate the pipe so that it goes around them.  Do not cut large roots that are close to the trees trunk without consulting an arborist.  If you can’t afford an arborist or other landscape expert at least giving it a lot of thought before cutting the roots.  Are there sufficient other roots to hold the tree?   You can severely weaken the tree and cause it to topple in a wind storm.  You might want to consider if it would be advisable to stabilize the tree with cables and stakes if you do cut the roots.