The project scheduled for your neighborhood is part of the City's program to upgrade the water and sewer system. Many of the older water and sewer pipes throughout San Diego have been scheduled for replacement because of their age, a history of leaks, breaks or other problems. The larger water pipes that serve streets are called mains. Smaller water pipes that extend from the main to each house are called services. Most of the water mains scheduled for replacement are located in the City's more established neighborhoods, and some of them have been in service for nearly 100 years. These older cast iron mains comprise less than 10 percent of our water system, but account for 60-80 percent of the water main breaks. Replacing these aging water mains with modern materials will help ensure safe and reliable delivery of drinking water well into the 21st century.

Many of the same neighborhoods that are served by old cast iron water mains often have sewer mains that are very old as well. The smaller sewer pipes that extend from the main to each house are called laterals. The sewer mains and laterals slated for replacement are made out of concrete or vitreous clay. These materials are far less durable and reliable than today's materials, which are much more resistant to root blockages and deterioration.

During the past 40 years, the City has replaced more than 600 miles of original concrete sewer pipe. Many of the aging sewer mains will be replaced at the same time as the water mains to help meet the goal of maintaining a safe and efficient sewage system for the region.

The City schedules many of these water and sewer main replacement projects for the same time and location to minimize the impact on the community. The City's Public Utilities Department and Public Works Department coordinate adjacent main replacement projects, which are generally grouped geographically and called Group Jobs.

In addition to the age and condition of the pipes, engineering plays a major role in deciding which mains will be replaced and when each project is scheduled. Replacing continuous segments of sewer or water mains in a neighborhood is crucial to improving the efficiency as well as the reliability of the system. While most Group Jobs involve the replacement of both sewer and water mains in a neighborhood, a few jobs are exclusively water or sewer replacements.

Sewer pipeline rehabilitation projects line old and deteriorated sewer mains and laterals with a hard plastic liner. This liner reinforces the old pipes, improves system reliability, and ultimately extends the service life of the old pipes without the need to create a trench to dig up and replace the old sewer main. In the rehabilitation process, the old pipes are accessed through existing manholes or cleanouts.

Because it does not require excavating, removing and replacing an entire pipeline, relining the existing pipelines is generally quicker and a more cost-effective alternative to digging up an entire pipeline, and creates less impacts to the community and environment.

To rehabilitate a sewer pipeline:

1. First, a crew and a small truck with equipment set up along the centerline of the street and videotape the existing condition of the old pipe. If during the pre-construction videotape a damaged section of main or lateral is discovered that is too great to be lined, then the Contractor will perform a "Point Repair." A point repair involves digging into the ground or street to fix a damaged section. This allows for the lining of the remaining main or lateral. Once the point repair is complete, the surface is restored to prior condition or better.
2. Then, the sewer pipe is cleaned to prepare the pipe for the lining process and the sewer pipes are reinforced with new plastic liners. Odor generation might result from a material called resin used to solidify the lining that is installed along the walls of the existing sewer main. The odor will dissipate as construction progresses and poses no danger to residents and homes.
3. After the main sewer pipe is lined, the below-ground laterals that connect to individual residences or business are located using the video taken prior to construction and using an above ground sensor. Once the location has been determined, the contractor will install a clean out at the intersection of the lateral and the edge of the right-of-way, so that the lateral can be lined to the main. Depending on the location, construction workers hand dig or use small machinery to excavate a 4-foot by 4-foot area to facilitate the installation of the clean out
4. Last, the newly relined sewer main and laterals are videotaped and inspected to ensure all contracted work is completed.

Sometimes a water main that is leaking or a sewer main that has been experiencing leaks or blockages will be added to a Group Job that is nearly ready for construction. That way, water or sewer mains in need of immediate attention can be replaced more quickly by adding them to a Group Job that is nearing the construction phase.

Construction work is performed by private contractors who meet set requirements and submit bids to the City. The City is required to award each construction contract to the lowest, qualified, responsible bidder. City engineers provide quality control monitoring to ensure the work is built according to the contract plans and specifications and is safe, reliable, and cost-effective.

Water service generally is not affected when the sewer mains are replaced in your neighborhood. If the water main that serves your home is being replaced, you will be notified in advance of any non-emergency service outages. Service to homes is temporarily shut down at the start of construction so crews can bypass the old main that is being replaced. There will also be a temporary service shutdown when the new main is reconnected at the end of construction. During construction, your household water will be supplied by temporary pipes called "high-lines."

High-lines are 2-inch diameter water pipes that are temporarily installed along the face of the curb and attached by a rubber hose to your water meter. The installation of high-lines is typically performed by the Public Utilities Department. These temporary pipes will supply water to your home as the old water mains are replaced. You may experience a slight drop in water pressure when high-lines are in use. The water in the lines may heat up during the day, much like the water in a garden hose that is warmed by the sun. Because these high-lines are placed above the ground, motorists and pedestrians should exercise caution around them. For added safety, an asphalt mixture is placed over the high-lines where they pass driveways and other high traffic areas. If a high-line leaks or breaks, please report it to the Public Utilities Department's 24-hour Emergency Services hotline at (619) 515-3525.

Water flushing is necessary for the disinfection of new water mains, recently repaired water mains, and temporary water high lines. Due to health reasons, super-chlorinated water, which is used to disinfect the new or repaired pipelines, cannot be delivered directly to customers and therefore needs to be de-chlorinated and flushed out of the system before being discharged to the environment. Flushing is also required to resolve water quality issues in the water distribution system due to stagnated water, potential contamination, removal of bio-film and sedimentation, and dirty water complaints from customers due to sediments and corrosion residues in the pipes.

Overall, pipeline flushing requirements make the capture and use of released flows difficult, particularly in cases of large diameter water mains. The location, volume and velocity of released water are already managed to avoid flooding of streets, erosion, excessive saturation of grounds, and damage to vegetation and streambeds. The City's Public Utilities Department has evaluated options to reuse and/or decrease the amount of water used for flushing. Public Utilities also contacted various supply agencies, and the California Department of Public Health (DPH) for input. DPH has indicated that there is currently no approved method to capture, treat and reuse flushed water for potable use due to water quality concerns. At this time, there continue to be no cost effective alternatives to the flushing policy.

Both the City's Public Utilities and Engineering Capital Projects departments work closely together to track, reduce and limit the amount of water necessary to meet water quality requirements for new water mains. Engineering Capital Projects Department has implemented a tracking form, used by contractors, to meter flushing water. This information is being used to more accurately determine if appropriate or excessive flushing water is being used. This information may also be used to revise contract documents and specifications related to flushing. The City is open to any and all new ideas that may reduce the need for water main flushing and/or help to recycle the released water, and continues to work with designers, contractors, other water agencies, and City departments to seek opportunities to minimize the amount of flushed water utilized.

The Public Utilities Department estimated in 2014 a cost of about $200 to capture and transport 4,000 gallons (tank truck) of flushed water. This $200 would save only $22.28 worth of water at the City?s commercial/industrial retail rate (5.35 HCF at $4.17 / HCF). It is estimated that for an average flushing event, 18 truckloads would be required to capture the flushed water. This would be at a cost of $3,600 for the capture of $400 worth of water. Increased project impacts to the community, due to increased traffic, pollution and noise would also result from such trucking activities.

Generally, water is discharged to storm drains and in many areas these storm drains discharge to natural streambeds helping to recharge groundwater and maintain riparian habitats in local canyons and creeks. Also, the water helps clean the storm drains. Accordingly, a portion of the water released due to flushing is beneficially used.

Group Jobs usually average about 12 months from the start of construction to completion. Work on each individual block typically takes the contractor about two to three weeks to replace the water main or sewer main. Sewer rehabilitation projects are typically completed in a shorter time period.

On Group Jobs, the sewer mains are generally replaced first throughout the entire project because they are farther underground and require a deeper trench than water main replacement. The new sewer main is installed in the street, and then the new laterals are connected to the existing sewer pipe that comes out of the home or business. This new lateral also includes a clean-out connection that is installed in the City's right-of-way at the property line, which is typically 10 to 25 feet behind the face of the curb.

Once the new sewer main, laterals and clean-outs have been installed and connected, the trenches are filled, compacted, and a temporary paving is installed on top. Approximately four to six weeks later, the sewer mains are further evaluated by a video camera to make sure there is no sagging and/or settling or debris inside. Once the sewer main passes the tests, a permanent concrete cap is poured to cover the trench.

The water main is replaced weeks or even months after the sewer main has been replaced. Once the high-lines are connected to water meters, a loop of water mains in the neighborhood is isolated and plugged. A new trench is dug so the old mains can be removed and replaced. As each section of water main is replaced, the trench is covered, compacted, and capped with temporary paving. Once the entire loop of water mains has been replaced, the mains are pressure-tested and sanitized before the individual water services are re-connected to the water meters. A new, larger water meter box will be installed. The temporary caps on the trenches are then removed and the permanent street repairs are performed.

It would be extremely difficult to safely manage two different large-scale utility projects on the same street at the same time. Opening two parallel trenches on a street poses a safety hazard. Replacing both the sewer and water lines simultaneously also would require the closure of the entire street because of the large area needed to excavate and work in two separate trenches. Additionally, a full street closure wouldn't leave room for emergency vehicles to get through. For these reasons, the sewer and water mains are not replaced simultaneously.

Putting a water main and a sewer main in the same trench is prohibited by health codes to avoid possible contamination of the water main in the event of a sewer line break. A minimum of 10 feet separating the water main from the sewer main is required.

Construction projects such as Group Jobs or pipeline rehabilitation projects are rarely accomplished without some disruptions to the pattern of everyday life. Before construction is allowed to begin, contractors are required to get approval for a traffic management plan for the affected neighborhood. The plan includes provisions for moving traffic through the area when work is underway, maintaining pedestrian access through the construction zone, and notifying residents when access to driveways or pedestrian lanes will be affected. When a street, driveway, or pedestrian access is to be temporarily closed, the contractor is required to notify the affected property owners and tenants in advance. The notice also will say how long the work will take to complete. The contractor is also responsible for providing proper access to homes and businesses during construction. Temporary no-parking zones may be established during construction in both business and residential areas. They will be designated by signs at the curb.

Yes. The contractor is required to set aside lanes so emergency vehicles can have access to all homes in neighborhoods where construction projects are underway. In the event of an emergency, the contractor will assist emergency vehicles as needed to provide access to all buildings and residences. All fire hydrants are kept in service during construction in the event of an emergency.

Working hours on construction projects in residential areas are generally from 7 a.m. to 3:30 p.m., although this can vary due to preparation time and individual project circumstances. Typically, construction work completed during a normal eight-hour shift will be covered and ready for traffic by the end of the shift. Open trenches will be covered by large metal plates secured in place with an asphalt mixture. In some business districts, work hours may be modified by the City Resident Engineer for each project to help business owners accommodate their customers.

A City-hired private contractor typically makes arrangements with owners of private property to use a vacant lot as a staging area to store equipment and materials during construction. If a vacant lot is unavailable near the construction area, equipment and materials such as pipe, sand and gravel may be stored temporarily on streets near the project. In most cases, the equipment and stockpiles of materials will move along as the construction project moves along.

When water mains are replaced in a neighborhood, a section of the water system covering several blocks is cut off and plugged so the mains can be replaced. The entire section must be replaced before any of it can be put back in service. It may take several months to finish the entire section, so all customers in that area will continue to receive their water from the high-lines. Once each section of main is installed, the trench is filled with a mixture of asphalt and gravel called "cold mix." This temporary paving allows the street to be reopened to traffic while the remainder of the project is completed. Once all the new mains have been replaced, they must be pressure-tested and sanitized by the contractor, then tested for purity by the City's Water Quality Lab. This process can take from several weeks to a month. Once this is completed, Public Utilities Department crews will return to your street to disconnect the high-lines and connect your water meter to the new water main. A new, larger water meter box will be installed. The high-lines will be removed when all the customers in the neighborhood have been connected to the new water main.

The City's Resident Engineer on each construction project monitors the construction daily and provides quality control assurance by verifying through testing that the materials used on each job meet the contract specifications. This includes all the pipes, joints, and connections before and after they are put into service. The Resident Engineer monitors the neighborhood traffic plan, the saw-cutting of the streets before excavation begins, trench shoring for worker safety, and the trench bedding before the pipes are laid. Inspection of the backfill and capping of the trenches, as well as monitoring the quality of the new street surface are also handled by the Resident Engineer.

Once the new mains are in place, the Resident Engineer oversees the pressure tests, bacteria tests and chlorination of the new water mains and the video evaluation of new sewer mains. In addition, the Resident Engineer's administrative role in any construction project includes handling any unforeseen construction and engineering issues that arise, authorizing monthly payments to contractors and coordinating the entire construction project from beginning to end.

After all the work is completed and has passed inspection, the contractor is required to repair your street so its condition is as good as when the project started. In most cases, trenches will be permanently capped with concrete, then a slurry seal is applied to the entire surface of the street. Slurry seal is a mixture of petroleum, sand, and a binder that helps the mixture adhere to the street. The slurry seal both protects the surface of the street and improves its appearance. In some cases, when the condition of a street is very poor, a layer of asphalt will be laid over the existing surface. On streets and alleys with concrete surfaces, the trenches will be capped with new concrete. This new concrete cap may initially differ in appearance from the existing concrete, but will fade over time.

Most pipeline projects are constructed within the public right of way. As such, it is expected that no private construction of hardscape, landscape or any other improvement shall be built within the City right-of-way without prior permits from the City of San Diego. If an unpermitted improvement is encountered within the public right-of-way, which impedes the progress of the project, the encroachment will be removed at the owner?s expense. Once the unpermitted improvement/encroachment is removed and the construction work completed, the area will be left in a safe properly graded fashion. The unpermitted improvements will not be restored.

Driveways, sidewalks,curb, gutters, parkways or any other improvement, which went through the permit approval process will be restored once the work has been completed.

At times, pipeline projects require going through existing easements to update the facilities. Per the easement agreement with the City of San Diego, there shall be no structure or hardscape built over the existing easements. Any structure or hardscape built must be removed at the cost of the resident. Once the unpermitted improvement is removed and the construction work is completed, the area will be left in a safe properly graded fashion.

Please see the City of San Diego Encroachment Maintenance and Removal Agreement (.PDF) if you desire to enter into an agreement allowing improvements under specific guidelines set forth by the City of San Diego.

The property owner should contact the City's Resident Engineer to provide information and initiate the claims process. Near the end of each project, the Resident Engineer prepares a "punch list" of final repairs, upgrades and enhancements needed to complete the job. Most minor repairs are made by the contractor at this time.

If you have any questions or comments about the Group Job in your neighborhood, call the Engineering Capital Projects Department construction project information line at (619) 533-4207, submit your inquiry online, or email engineering@sandiego.gov.