A 12" square catch basin collects water from my driveway and transports it under the lawn to adjacent stream about 150 ft away via 4" corrugated buried pipe. They used corrugated covered w/stone (vs pvc) (20 yrs ago) so as to also collect surface water from the poor-drainage yard. The drain pipe is down to a trickle due to tree roots that infiltrated the 4" pipe. In a downpour the basin overflows. In the past (2X) it was cleared by a roto rooter type power auger. This time it can't get through and they are suggesting that a hi-pressure jetter could do the trick (maybe) at a cost of $600-800. A lot of money but much less than excavating, digging up & replacing the 150 ft pipe. Does the jetter stand a a chance or am I throwing money away? It could also possibly damage the existing pipe but that might not matter if the pipe needs to be replaced anyway. Would appreciate any comments and perhaps alternate approaches to this problem. Thank you.
Listen, if roots are infiltrating, you least expensive solution is to dig it out, retrench, and put in a new drain. You may also wish to trim back the roots, and make a wider trench with heavier gravel at the point where the tree is infiltrating to slow it down.
Why is this cheaper? Because it's going to happen again and again, and you are going to be forced to replace it again anyway.
If the French drain is 20 year old anyway, it's probably due for replacement here or there along the line.
Use PVC where it's being infiltrated, and make it a longer than apparently needed because eventually the roots are going to find the ends of the PVC.
Do yourself a favor and save money in the long run. Trying to save money today is going to cost you even more later, and maybe even have to spend it right away if the jetter doesn't do the trick. If it does the trick you'll be facing the problem again next year.