We discovered we have issues with our wastewater lateral and it needs to be replaced. Not to get too into the details but where we expected to find a 4” cast iron lateral that could be cleaned and lined we instead found a 6” terra cotta lateral with multiple issues that mainly stem from extensive root infiltration from the maple tree that was planted about 4 feet away from it.
The photo shows the tree and very close to where the line runs. The plan from our contractor is to dig up either side of the stairs and replace with PVC since lining isn’t possible. The excavation is planned to be only in the mulch beds shown, since the main runs in the grass about three feet away from the end of the bed. The existing terra cotta will be left under the stairs and to the main and lined then connected to the PVC.
Our concern is how close the excavation is to the tree and how it will impact the trees health. Ideally we would use trenchless but that isn’t really an option, and rerouting isn’t really possible due to needing to reuse the existing house and main connections. So what should I be sure our contractor is doing to best protect the tree, and how should we take care of it once everything is complete. We are expecting some die off in the canopy but it’s a really healthy tree so we are hoping that with good care we can save it overall.
I’m not saying laterals have no nutrients, but the concentration and type of nutrients are very different between laterals and septic tanks.
Sewage in laterals is pretty dilute. Septic tanks (the tank, not the drain fields) are where the solids collect. They break down a bit over time and particulate forms of nutrients become soluble and more easily taken up by plants.
The sewage in the fields is also generally more strong than sewage that goes to municipal or shared systems because it’s passing though the tank and taking up some of those newly solubilized nutrients on the way to the field.
The tree is absolutely going to get less water when it’s repaired, but I’d be doubtful that the nutrient level will change all that much.
I hadn’t considered this. I imagine soaps and such also don’t help things in a lateral since a lot of the water will have some sort of soap in it (anything other than a toilet flush, and those will be followed by at least a small amount from hand washing).
Maybe it’s because there’s always some water being pumped into a field, but the grass always grows like hell on a field. Effluent will also have quite a bit of nitrogen because urine=urea.