Private Utility Locating in Portland: Old Neighborhoods, Sewer Laterals, and Oil Tanks
Portland is one of the harder places we work. The reason is not lot size. It is the age of the housing infrastructure. Most homes in the inner neighborhoods were built before 1950, and much of what is buried in those yards was installed by people who never recorded it. 811 marks the utility company's lines up to the meter. Everything on your side of the meter is your responsibility, and in Portland that usually includes lines you did not know were there.
What we find in Portland yards
Every property is different. These come up repeatedly across Multnomah, Washington, and Clackamas counties:
Sewer laterals. Older Portland homes have a private sewer line from the house to the main. Some still share a party lateral with a neighbor. The city does not mark these (they are yours from the property line in), and they are the line most often struck during driveway and foundation work.
Heating oil tanks. Thousands of Portland homes were heated with oil. Many tanks remain in the ground, with fill and vent lines running to the house. If you are buying, selling, or excavating, you will want to know where the tank is before the excavator finds it.
Abandoned lines. Old galvanized water services, dead gas runs, and early electrical feeds to garages. Abandoned does not mean removed.
Feeds to detached structures. Power and water to garages, studios, and the ADUs built across the city over the last ten years.
Irrigation and low voltage. Sprinkler mains, controller wire, and landscape lighting. These are shallow and usually sit right where new fence posts are going.
Why 811 marks are not enough here
811 does its job, which is to mark public utilities up to the service point. On a Portland lot, that leaves the lateral, the private water service, every feed to an outbuilding, and every abandoned line unmarked. The paint on the pavement at the curb shows where the main is. It says nothing about the 40 feet between the sidewalk and your foundation, which is where the digging actually happens.
When to bring us in
You will want a private locate before:
Sewer repair or replacement (we find the lateral and its full route, not just where it exits the house)
Driveway, patio, or retaining wall work, especially on a sloped lot
ADU or garage conversions that need new utility runs
Oil tank decommissioning or a pre-sale inspection
Tree planting or removal where roots and old lines share the same ground
For contractors, any excavation on an older Portland property should be located before equipment arrives on site.
How we do it
We use three methods. Electromagnetic locating covers anything metallic or anything we can put a signal on, which includes most water, gas, and electrical lines. Ground penetrating radar picks up plastic pipe, oil tanks, and disturbed soil. For sewer laterals, we push a sonde through the line and follow it from the surface to get the exact route and depth.
Every line is painted in the standard APWA colors, so your crew reads our marks the same way they read 811's. If you need documentation for a permit or a client, we can provide a sketch or a GPS/RTK file of the findings (when selected at time of service).
Two Portland-specific notes. Depth readings are estimates. On a lot that has been dug up several times over the decades, you will want to pothole before you trust them. And if we find an oil tank, we can mark it, but decommissioning is a separate job with its own DEQ paperwork.
Getting on the schedule
Our Portland office covers the metro area on both sides of the river, from Vancouver to Wilsonville and out to Gresham and Hillsboro. Send us the address, what you plan to dig, and any drawings or permits you have, and we will get you a time. Contractors with regular work can set up an account and book without a quote each time.
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