Wastewater Enterprise
525 Golden Gate Avenue, 13th Floor
San Francisco, CA 94102
T 415.554.3155
F 415.554.3161
TTY 415.554.3488
Sewer Inspection and Replacement Program Semi-Annual Update, May 2022
The Wastewater Enterprise (“WWE”) owns, operates, and maintains approximately 800 miles of sewer mains equal or smaller than 36” in diameter (“small diameter gravity sewers”). In addition, WWE replaces sewer service laterals with structural deficiencies located on the pipe portion extending from face of curb to the sewer main (“sewer lateral”). There are approximately 160,000 sewer laterals. The SFPUC Commission has established the goal of completing a rolling average of approximately 15 miles per year of rehabilitation or replacement (R&R) of small diameter gravity sewers. Laterals do not have a specific annual R&R target, however these are inspected and replaced typically during construction of the sewer main R&R projects, with about 40% of existing laterals replaced as part of each R&R project. This report summarizes progress on the gravity sewer R&R program including asset cleaning, condition assessment, and R&R of public mains and laterals.
Renewal & Replacement
The WWE Collection System R&R Program has a capital budget of $112.2M for Fiscal Year 2021-2022, broken down by major activity as shown in Table 1. Primary activities under the Program include sewer cleaning, condition assessment (inspection), renewal and replacement of sewer mains, and similar actions for sewer laterals. The Sewer Improvements budget in FY 21-22 of $81.2M is funding 13.5 miles of sewer mains, slightly lower than the 15-mile target. The new mileage is lower than the target due to increases in construction bids, which limited the milage anticipated for award in the FY period.
Table 1: FY21-22 Collection System R&R Program Small Diameter Sewers & Laterals Sewer Improvements (R&R) – Small Diameter $81,228,000
Condition Assessment – Small Diameter $3,940,000
Condition Assessment – Sewer Laterals $520,000
Spot Sewer Repair Program $26,476,000
Total $112,164,000
The program maintains the existing functionality of the sewage collection system and includes planned and emergency repairs and replacement of structurally deficient sewers. The R&R Program budget is based on an annual target of 15 miles. Individual projects vary from less than one and up to three miles typically and are most often completed as part of inter-departmental capital projects such as the Geary BRT corridor and other MTA projects, and as part of the Public Works paving program. Actual mileage awarded and completed in any single FY will vary based on the timing for initiation and construction for joint projects and variable bid results that may limit mileage under the FY budget.
WWE is shifting focus to utilize more trenchless construction methods for sewer main and lateral R&R, including cured-in-place-lining (CIPP), pipe bursting, sliplining, and alternative pipe materials. Trenchless construction methods are industry best practice and provide the benefits of substantially lower average cost per mile, shorter construction times per mile, and lower overall disruption to the public from the construction activity. As reflected in the newest 10 year CIP, WWE’s goal is to have 50% or more of gravity sewer R&R work done using trenchless construction methods within the next 7 years.
Spot S
ewer Repair Program
The Collection System R&R Program includes funding of $26.4M for the Spot Sewer Repair Program, which has a current target of 1,100 repairs per year. In prior years, approximate 80% of these repairs have been done with outside contractor resources and 20% using a Public Works crew. Spot repairs at this level of activity have been limited to reactive repairs of already failing pipes and laterals. As part of the changing asset management
Commission Meeting: May 10, 2022
FY21-22 Annual Sewer Inspection & Replacement Program Update
strategy for the gravity sewers, the annual spot repair target will be doubled in future years so that proactive spot repairs can be deployed to restore pipe structural integrity before failure and will rely more on trenchless spot repair construction methods. Proactive spot repairs will provide the following benefits:
1. Cost Efficiency: less risk is placed on the awarded contractor by having scopes of work identified prior to bid, allowing the contractor to schedule and plan work up front instead of reactive, short notice work locations and conditions. Trenchless spot repair also lowers the unit cost by 30% or more vs. open cut methods.
2. Public Disruption: assessing repair needs ahead of bidding and reflecting the work conditions allows maximum use of trenchless methods, decreasing street excavations and disturbances.
3. Overall Construction Quality: City construction inspection resources will be able to plan and deploy with more lead time to plan and deploy adequate coverage of the construction, compared to the relatively limited inspection coverage for reactive and short notice work.
One notable change to the spot repair program is the ending of use of Public Works crews beginning with FY 22-
23. This change has been evaluated for several years between SFPUC and PW due to the increasingly limited capabilities of the crews, substantially higher costs, and lower productivity compared to the contractor resources. The two departments have worked cooperatively on this transition, including the transfer of 11 staff from PW to SFPUC WWE, where these staff will work on gravity sewer activities such as cleaning, condition assessment, and service calls. The capital budget funds used for the PW crews will be repurposed to increase the mileage capacity of the next round of bid projects.
Condition Assessment
WWE Collection System Division (“CSD”) performs condition assessment on small diameter sewer mains.
Condition assessment generally consists of cleaning, inspection, and NASSCO Pipeline Assessment Certification Program (“PACP”) coding. Due to the large quantity of assets, CSD prioritizes sewer main condition assessment by grids with a risk-based asset management approach, known as the Collection System Asset Management Program (“CSAMP”). Once condition assessment is performed, renewal and replacement projects are developed. CSAMP is based on the Total Risk, which is calculated by Likelihood of Failure and Consequence of Failure: Likelihood of Failure is a score that considers sewer main expected remaining useful life and age.
Likelihood of Failure is further refined by physically assessing actual sewer main condition by Closed Circuit Television (“CCTV”) video inspections. Consequence of Failure is a score that considers a variety of potential impacts, including location-specific risks, public safety, and economic factors. Table 2 summarizes the overall progress of the Sewer Inspection & Replacement Program activities for Fiscal Year 2021-2022 through Q3.
System Maintenance is defined as regular maintenance activities completed by WWE CSD Sewer Operations, which includes cleaning, inspection, and NASSCO PACP coding for condition assessment. These individual activities are identified to illustrate different efforts. Condition assessment includes coding media sources from prior years and 3rd Parties such as PG&E’s cross-bore elimination program inspection mileage.
Sewer Renewal & Replacement: Miles of Sewer Mains Awarded is defined as the mileage of sewer mains that were included as part of construction contracts awarded this Fiscal Year. These data sets are further broken to illustrate different contract mechanisms for project delivery. Note contract award is approximately 2-3 years prior to construction completion.
**System Renewal & Replacement: Miles of Sewer Main Renewed / Replaced is defined as contracted collection system asset replacements and rehabilitations that have been installed during the current Fiscal Year. After award, completion may take 2 to 3 years typically.
***System Renewal & Replacement: Locations of Spot Repair is defined as individual spot repair locations for both mains and laterals, tracked by number of locations for spot repairs.
Commission Meeting: May 10, 2022
FY21-22 Annual Sewer Inspection & Replacement Program Update
Table 2: Fiscal Year 2021-2022 Sewer Inspection & Replacement Program System Maintenance: Miles of Sewer Mains Cleaned
Description Q1
Jul 1-Sept 31
Q2
Oct 1-Dec 31
Q3
Jan 1 - Mar 31
Q4
Apr 1 - Jun
30 Cumulative
Total as of
03/31/2022
CSD Sewer Ops 21.6 12.7 21.7
SFPUC Inspection Contractor* 0.9 1.1 2.9
Total Miles of Sewer Mains Cleaned 22.5 13.8 24.6 0.0 60.9 System Maintenance: Miles of Sewer Main CCTV Inspected
Description Q1
Jul 1-Sept 31
Q2
Oct 1-Dec 31
Q3
Jan 1 - Mar 31
Q4
Apr 1 - Jun
30 Cumulative
Total as of
03/31/2022
CSD Sewer Ops 14.4 9.0 16.9
PG&E** 0.0 0.1 0.01
SFPUC Inspection Contractor* 2.1 0.9 2.6
Total Miles of CCTV Inspection 16.5 9.9 19.5 0.0 45.9
System Maintenance: Miles of Sewer Main Inspection Media Coded for Condition Assessment Description Q1
Jul 1-Sept 31
Q2
Oct 1-Dec 31
Q3
Jan 1 - Mar 31
Q4
Apr 1 - Jun
30 Cumulative
Total as of
03/31/2022
CSD Sewer Ops 11.7 7.0 5.2
CSD Consultants 1.0 3.3 2.1
SFPUC Inspection Contractor* 0.5 1.9 3.1
Total Miles of Media Coded 13.1 12.2 10.4 0.0 35.7
System Renewal & Replacement: Miles of Sewer Main Awarded for Renewal and/or Replacement Description Q1
Jul 1-Sept 31
Q2
Oct 1-Dec 31
Q3
Jan 1 - Mar 31
Q4
Apr 1 - Jun
30 Cumulative
Total as of
03/31/2022
R&R (PUC Led Projects) 1.0 0.9 1.0
R&R (Joint Projects) 0.8 5.0 1.3
Total Miles Awarded for Renewal /
Replacement 1.8 5.9 2.3 0.0 10.0
System Renewal & Replacement: Miles of Sewer Main Renewed / Replaced* Description Q1
Jul 1-Sept 31
Q2
Oct 1-Dec 31
Q3
Jan 1 - Mar 31
Q4
Apr 1 - Jun
30 Cumulative
Total as of
03/31/2022
R&R (PUC Led Projects) 0.1 0.5 0.6
R&R (Joint Projects) 0.5 0.6 0.7
Total Miles Renewed / Replaced 0.6 1.2 1.2 0.0 3.0
System Renewal & Replacement: Locations of Spot Repair*** Description Q1
Jul 1-Sept 31
Q2
Oct 1-Dec 31
Q3
Jan 1 - Mar 31
Q4
Apr 1 - Jun
30 Cumulative
Total as of
03/31/2022
Repairs Completed by Contractor 213 181 In Progress
Repairs Completed by SFPW BSSR 53 50 46
Total # of Repairs Completed 266 231 46 0 543