Important EcoTech Documents

For additional information regarding our service lines, we have attached supplementary documents for your reference.

Heating Oil Tanks

Radon Mitigation

Seismic Retrofits

Septic Tanks & Cesspools

Septic Tank Decommissioning

Septic Tank Decommissioning Common Questions

What is a septic tank?

A septic tank processes wastewater from the home and consists of two main parts, the tank and a drain field.  It encompasses a piping connection, allowing the waste to flow from the home, through the tank and into the drain field, these connections are made through a T pipe, allowing liquid to enter and exit without disturbing the surface above.  The septic tank treats the wastewater and allows the separation of solids and liquids, once broken down the solids remain in the tank while the liquids drain into the leach field.

Septic tanks may be concrete or metal, 5 to 7 feet long and 5 to 7 feet deep, and will be located 5 to 30 feet away from the home.

Are there dangers associated with abandoned septic tanks?

Septic tanks that are buried underground are susceptible to corrosion, thus weakening the stability of the structure. The instability can cause the system to collapse, causing serious injury or death. Septic tanks contain dangerous gases due to the breakdown of decomposing matter, falling into a tank can cause the possibility of being overcome by noxious gases.

How do I know if I have a cesspool or septic tank on my property?

Within the Portland Metro area, there are two methods that may help determine if you have a cesspool or septic tank on your property:

  • For a general rule:
    • If your home is east of the Willamette River, most systems installed were cesspools.
    • If your home is west of the Willamette River, most systems installed were septic tanks.

How do you find a septic tank?

The location of the system would need to be determined by sending out a technician to the property.  The technician locates the main plumbing stack that comes through the roof and visually extends a straight line from the exterior foundation line.  From the foundation, the technician would follow the visual straight line out to the septic tank, between 5 to 30 feet from the home.

Decommissioning of a septic tank

How do you decommission a septic tank?

The proper septic tank decommissioning permit will need to be obtained for the city and/or the county the septic system is located in.

EcoTech uses excavation equipment to dig to the top of the structure to expose and open the septic system.  Once accessed and per OSHA regulation, shoring of the area around the system is completed to prevent collapse of the shaft and to ensure the safety of our technicians.

Our technicians will then inspect the interior of the tank, and pump any liquid or sludge that may be present.

Contingent on the city and/or county permitting process, inspection of the system may need to take place prior to filling the tank.  Inspection may also need to take place after the tank has been filled, depending on permit requirements.

When the tank has been pumped of all sludge, and all relevant inspections completed, the tank can be filled with either sand or gravel.  Once the septic tank is decommissioned, the technicians would replace the soil overburden, bringing the area back to surface grade, along with a closed permit for the decommissioned septic tank.

Septic Tank Decommissioning

Septic Tank Decommissioning – Dug down and exposed septic tank

Septic Tank Decommissioning

Septic Tank Decommissioning – Roped off septic pit for safety

Septic Tank Decommissioning

Septic Tank Decommissioning – Broken terracotta pipe, this is part of the system that allows wastewater to drain from the home. When the pipe is broken, this allows waste to seep into the yard.

Septic Tank Decommissioning

Septic Tank Decommissioning – Filled septic tank, with T piping junction of metal pipe to terracotta pipe.

Septic Tank Decommissioning

Septic Tank Decommissioning – Filled septic tank, with T piping junction of metal pipe to terracotta pipe.

Septic Tank Decommissioning

Septic Tank Decommissioning – Filled septic tank, ready for overburden to be replaced

For more information on local cities requirements on septic tank decommissioning within the Portland Metro area, please click on the following links:

Cesspool Decommissioning

Cesspool Decommissioning Common Questions

What is a cesspool?

In the most basic terms a cesspool is a constructed underground vault for the disposal of liquid waste and sewage. Cesspools are made of loose-fitting brick or concrete rings, which allows the liquids to seep through the brick gaps or perforations within the concrete rings, leaving the solids behind.

Original cesspools are typically 3- to 4-feet in diameter and usually located 10 feet away from the exterior foundation of the home, in line with the main 4” sewer-vent pipe. Homes with crawlspaces or slab on grade construction have cesspools typically located about 3- to 5-feet below ground surface, while homes with a basement will commonly be 8- to 10-feet below the ground surface.

Cesspool Decommissioning

Cesspool Decommissioning – Technician performing an onsite cesspool evaluation

Why should I worry about a cesspool?

Abandoned cesspools can become unstable and collapse, causing a sinkhole or completely collapse within the yard. Falling into a collapsed or collapsing cesspool, that may contain liquids and sludge, can cause serious injury or death.

If you suspect that a sinkhole is forming within your yard, the area should be roped off immediately to prevent anyone from falling into the opening and a qualified expert should be contacted for assistance.

How do you find a cesspool(s)?

The likely location(s) of the cesspool(s) would need to be determined by sending out a technician to the property and conducting research through public records, if available.  The on-site technician locates the main 4” main sewer-vent pipe that extends through the roof and matches it up to information gained through public records.  From the foundation, original cesspools are usually 10’ from the home. If multiple cesspools are located on the property, they can generally be found through diagrams within public records. Following the original plumbing, gaining information through public records and physically probing to them is the most reliable way to find the cesspool(s).

 

Cesspool Decommissioning

Cesspool Decommissioning – Cesspool marked out for excavation

Decommissioning of a cesspool

How do you decommission a cesspool?

EcoTech uses excavation equipment to dig to the top of the structure to expose and open the cesspool. Once the cesspool lid is removed, our technicians will then inspect the interior of the cesspool, pump any liquid or sludge that may be present, and completely fill the cesspool with gravel or sand. After the decommissioning has taken place, the technicians replace the soil overburden, bringing the area back to surface grade

The proper cesspool decommissioning permit will need to be obtained for the city and/or the county the cesspool is located in.  An inspection may also need to take place, after the system has been filled, depending on the county. Multnomah County will always require an inspection of the filled cesspool, prior to the decommissioning permit being finalized and the overburden replaced. If an inspection is required by the city/county, and a permit pulled for the cesspool decommissioning, once approved, the permit will be closed with the city.

 

Cesspool Decommissioning

Cesspool Decommissioning – Cesspool found, constructed out of loose fitting bricks

Cesspool Decommissioning

Cesspool Decommissioning – Cesspool found, constructed of concrete rings

Cesspool Decommissioning

Cesspool Decommissioning – Cesspool filled with sand, excavation fenced off and ready for inspection

For more information on local cities requirements on cesspool decommissioning within the Portland Metro area, please click on the following links:

Please note: although most of these links will reference septic tanks, the decommissioning processes is relatively similar.