Inflow and infiltration (I&I for short) are when stormwater and groundwater enter the sanitary sewer system. I&I can lead to sewer overflows during and after heavy storms, when flows can be ten times greater than normal. Overflows could damage household basements, overload wastewater treatment facilities, and pollute the Willamette River.

• Inflow originates from stormwater collection systems, such as catch basins and roof gutters that were historically connected to the sanitary sewer system under less stringent standard than those of today.
• Infiltration occurs when groundwater enters the sewer system through cracks, breaks, or defects in sewer mains, laterals and manholes.

Reducing I&I helps protect public health and safety while lowering costs for ratepayers. To achieve this, the City implemented the I&I Program - dedicated to identifying and correcting I&I sources. 

Why Repairing or Replacing Lateral Lines Matter

• If your sewer lateral needs repair or replacement, the City's Lateral Program can save you money by covering the cost of eligible work. Without the program, a typical inspection could cost a homeowner about $100, and repairs or replacement might cost thousands.
• Keeping laterals in good condition helps prevent rainwater and groundwater from entering the wastewater treatment system. This reduces treatment costs and helps keep resident's monthly utility bills lower by avoiding the need for larger pipes, pump stations, or upgrades at the Clackamas County water resource recovery facility.
• Healthy laterals also reduce the risk of sewer backups into homes, streets, and streams - protecting both your property and the environment.

What the City is Paying For

We have a grant from Clackamas County’s Water Environment Services, so we’ll pay for the following work:

• Lateral inspection: We’ll pay to inspect your lateral and mark it’s location. Even if we don’t find anything wrong with your lateral, you can request a copy of the inspection.
• Lateral repair or replacement: We’ll pay for any needed repairs or replacement so no extra water can seep into cracked or deteriorated pipes.
• Nonconforming laterals: We’ll pay to have nonconforming “party line” laterals separated so each property has its own connection to the mainline.
• Improper roof drains: We’ll pay to disconnect improper roof drains from the sewer system.
• Post-repair restoration: We’ll pay to repair any damaged patios, sidewalks, or hardscaping and cover landscaped areas with appropriate grass seed or bark chips.

What Happens First?

Investigation of Laterals

We’ll inspect properties’ sanitary sewer laterals for defects or conditions likely to cause (I&I). We’ll do this via CCTV, and we’ll paint and/or place markers on the property to show where the lateral runs, from the right of way to the building face. 

What Happens Next?

Repair or Replacement of Laterals

The investigation will show which laterals are defective or in a condition likely to cause I&I. We will not need to repair laterals that are in good condition.

We’ll contact the homeowner if their lateral needs repair or replacement.

What to Expect During a Replacement or Repair

We appreciate every property owner who participates in our lateral program. We’ll do our best to make sure your replacement or repair goes smoothly.

We’ll start by giving you a plan that shows the proposed work and describes all the impacts — both temporary and permanent.

• The plan may call for extensive digging in your yard, some digging, or none at all.
• The contractor will place flags or paint markings to help you match the plan to your yard and to assist them during construction. Please don’t disturb these markers.
• The plan will clearly state what you will need to do — if anything.

Next you’ll review and approve the plan. It’s your chance to bring up any concerns and ask for any changes. 

After you approve the plan, we’ll wait at least 10 days for you to do what the plan asks -  such as moving plants or small trees.  

• Failure to move plants or small trees as requested within the waiting period will result in removal by the contractor without replacement or compensation.    
• If the plan affects a lot of landscaping (bushes, small trees, etc.) or hardscaping (patios, decks, etc.), we’ll wait 24 days.
• You can ask for additional time, up to 24 days total.
• Any change to the plan will start a new wait period (with any requested extensions).
• If you don’t live at the property, notify your tenant during this wait period. Tell them the construction date and impacts.

After the wait period:

• The contractor will let you or your tenant know that work is about to start.
• If you didn’t move plants or trees according to the plan, the contractor will remove them and not replace them.
• The contractor will interrupt your sewer service for a maximum of one day (7 a.m. to 5 p.m.).

After replacement or repair:

• The contractor will close and seed any excavations, repair any hardscaping (patios, decks, etc.), and generally clean up.
• The City will guarantee the function of the lateral and the quality of the site restoration for one year. After that, full maintenance responsibility for the lateral and any other required repairs passes to the property owner.

Lateral Repair Methods

We’ll repair most laterals via pipe bursting — running a new pipe through your old pipe, bursting the old pipe as it goes.

If we need to take a new path, we’ll likely use directional drilling (boring underground). The impacts of this method are similar to pipe bursting, with the only excavation on your property being near your building.

Sometimes we need to dig a long trench to completely remove and replace a lateral.  We’ll do this if the defects found in your lateral are too severe for us to use pipe bursting, but we still want to follow the original alignment.

Occasionally we use Cured-In-Place Pipe Lining (CIPP). The final installation quality is not as dependable, so we use it only where we can’t use other methods.

Whatever method we use, the contractor will ensure the ground is smooth and seeded afterward and will repair any damage to hardscaping. Also: More than 10 feet from the lateral, the contractor will repair any damage to prior condition or better. This protects you just in case the contractor moves outside the work zone, which is very rare.

These methods are similar to those used for sewer mains. (Learn more about construction methods.)

What if I Have a Nonconforming Sewer Lateral?

The City code requires individual properties to have direct and independent connections to the public sewer mainline. Typically, a nonconforming sewer property does not have a separate lateral connection to the mainline or the property's lateral crosses another property's lot. This situation is commonly referred to as a “party line.”

As part of this program, we’ll pay to have your nonconforming lateral separated so each property has its own connection to the mainline.

What if My Roof Drain is Improperly Connected?

We want to ensure that no extra rainwater (also called stormwater) gets into the sewer system because it can overwhelm the treatment plant. We plan to treat stormwater separately.

If your roof drain is currently connected to the sewer system, we will disconnect it for you so it will be a proper connection. We’ll install a splash block (a rectangular piece of plastic or concrete that goes under the end of the downspout) and cap the ground connection. If needed, we’ll also pay for a stormwater lateral.