1 During the installation of sewage pipes, careful inspection of the location and or the selection of tree species should be considered when planting to prevent the growth of roots in sewer lines. Cities must inspect plumbers' connections to the main sewage lines. Homeowners should be aware of future problems with roots and avoid deep rooted or fast-growing trees such as willow trees that are quick growing and have long reaching roots.
Physical control: isolating the sewage lines from roots is done by pipe replacement and re-lining and tree removal.
2 Pipe replacement means digging up defective sewage lines and replacing with new ones. New pipes must have airtight joints to prevent root infestation. Pipe replacement damages property, disrupts traffic, and is costly. If the pipe risks failing and collapsing then replacement is the best course of action.
3 Pipe relining: Sewage lines can be refurbished by pulling a seamless pipe through the existing pipe – this is called “slip-lining” . A technology called “Cured-in-Place” lining inflates and cures a softcore plastic tube that fits the shape of the pipe. A robot makes connections between liners.
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These technologies address root infestation and can cure some structural defects and are less disruptive. It is very effective against further root infestation, however it can be more costly than pipe replacement. Nevertheless root infestation may return and chemical control may be needed.
4 Tree removal: if the offending tree is located, then removing the tree may be the best solution. However even though the tree may be removed, the tree stump must be removed as well and the roots need to be treated chemically with basal application herbicide.
Mechanical control: this is the use of tools and devices that can cut and remove the roots in sewer lines. The major advantage is that it relieves a blocked line immediately. Chemicals can be dangerous and ineffective when dealing with roots. A blocked sewer is typically a municipal emergency that requires a mechanical device to alleviate the the clog or blockage. The major disadvantage of mechanical control is its lack of long-term effectiveness and roots grow back heavier when cut. This method is best used in combination with chemical control.
5 Drilling machines, coil rodders, are manual or engine driven flexible steel cables that turn augers or blades through the sewage line. Mainly used by plumbers to relieve blocked lines from homes to the main line, but rarely used for larger main line pipes.
6 Rodding machines use flexible steel rods with rotating augers, corkscrews or blade cutters in small pipes up to 12 inches in diameter.
7 Sewer Jetter: also called flushers, flush trucks, water jetter, jet rodder, jetting machine, jet truck and hydraulic sewer cleaners are high pressure water pumps with a hose reel, a water tank and use a ½ inch to 1 inch diameter jetter hose. Rear facing water spray nozzle openings self-propel the jetter hose forward, and nozzle openings towards the front cut and clean the line of debris. The rear facing water spray nozzle flushes debris back to the manhole or catch basin for removal. Nozzle heads are also available with spinning root cutters that are water propelled.
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8 Winches : drag machines or bucket machines are power driven winches that pull brushes with porcupine like scrapers and buckets through the sewerpipe. Typical application is in large diameter lines, where a jetting machine is too small for the job. They can remove large volumes of debris.
Chemical root controls
Most root control products, as most chemicals used to kill plants, are herbicides. Herbicides destroy plants by systemic or contact action.
9 Systemic herbicide is absorbed by roots that carry the agent through the plant over two weeks or more to be effective.
10 Contact herbicides cause quick death and a localized effect at the point of contact of the plant.
Roots in sewer lines’ growth only worsens with time. Jetting, rodding and chemical applications are only temporary solutions to a longer-term problem. To prevent an infestation of roots in sewer lines, remove the offending tree or brush or replace the cracked line that is letting in the roots.
Although usually left to the professionals, see how DIY homeowners can tackle this nasty problem in the next section.