Answer: For wastewater applications involving older infrastructure (like 1950s-era manholes and ductile iron pipe), choosing the right locator depends on the specific target and depth. Here's what we recommend based on the use case:
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Manhole covers & valve boxes:
The Fisher FPID2200 or M-Series Magnetic Locators (like the M97 or M66) are excellent choices. These are optimized for locating buried ferrous objects under pavement or soil, even several feet down. -
Iron pipe (4" diameter or larger):
The TW6 Line Tracer is a strong candidate, especially for accessible pipe. It's highly sensitive and ideal for detecting and tracing ferrous pipelines. However, it does require a bit more experience to use effectively. -
Water service laterals:
For tracing water laterals, the TW82 or TW82P Active Line Tracer is recommended. It allows for direct connection or inductive tracing and gives you depth estimation as well. -
Deep ferrous targets (24" or deeper):
If you're trying to detect ductile iron pipe buried more than 24", a magnetic locator like the FPID2200 is your best all-around option. It provides excellent depth for iron targets but may depend on the pipe's diameter and wall thickness. In some cases, you might need to field test to confirm detection range.
Note:
If the targets are under pavement (like 4” of asphalt), both magnetic locators and line tracers will still work effectively—just be sure you're targeting ferrous metal and not relying on detecting plastic or non-metallic materials.