27420-05 Sanitary Sewer Inflow & Infiltration (I&I) Assessment - John Duckett Basin

September 9, 2026
To: Interested Parties
Re: Request for Proposals (RFP)
Sanitary Sewer Inflow and Infiltration (I&I) Assessment
John Duckett Basin
Job No. 27420-05
Dear Prospective Consultants:
The Las Gallinas Valley Sanitary District (District) is seeking proposals from qualified firms to
perform a wet-weather flow monitoring study and inflow and infiltration (I&I) assessment of
approximately 163,000 linear feet of gravity sewer in the John Duckett Basin. The purpose of the
study is to locate, quantify, and rank the sources of I&I within the basin so that the District can
prioritize rehabilitation spending on the segments that will yield the greatest reduction in wet-
weather flow.
If you would like your firm to be considered, an electronic copy of your proposal in PDF format
must be emailed to the attention of Jasmine Diaz at jdiaz@lgvsd.org cc: engineering@lgvsd.org
with the project name as subject heading no later than 2:00 PM on September 22, 2026. Award of
a contract for this RFP is tentatively scheduled for October 1, 2026.
Because the twenty-four (24) month monitoring period must capture the winter wet-weather
season from its onset, the District intends to have sensors installed and operating no later than
December 1, 2026. Proposers should confirm in their proposals that they can meet this date.
Please contact Jasmine Diaz via email at jdiaz@lgvsd.org if you have any questions related to the
contents and requirements of the RFP. Questions received after the inquiry deadline of September
15, 2026 may not be addressed.
Sincerely,
Jasmine Diaz, PE
District Engineer
101 Lucas Valley Road Suite 300 * San Rafael, CA 94903 * 415.472-1734 * Fax 415.499-7715 * www.lgvsd.org
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
REQUEST FOR PROPOSALS
SANITARY SEWER INFLOW AND INFILTRATION (I&I) ASSESSMENT
JOHN DUCKETT BASIN
1. BACKGROUND
Las Gallinas Valley Sanitary District (District) is located in Marin County, California between central
San Rafael and Novato. It was established in April 1954 under the Sanitary District Act of 1923 and
provides wastewater collection, treatment, and recycling to more than 30,000 customers in the
Santa Venetia, Terra Linda, San Rafael Meadows, Marinwood, Lucas Valley, and other communities
of San Rafael. The District's jurisdiction spans approximately 9.5 square miles from Hamilton Field
to the north, San Pablo Bay to the east, central San Rafael to the south, and Marin County Open
Space Reserves to the west.
The District's collection system includes 34 pump stations, approximately 3,056 structures
(including 2,520 manholes), and 3,108 active gravity sewer mains. The District also operates an
advanced secondary wastewater treatment plant and a 300-acre reclamation area adjacent to San
Pablo Bay.
Portions of the collection system experience substantial increases in flow during and following
storm events. This wet-weather flow consumes conveyance and treatment capacity, increases
pumping and treatment cost, and elevates the risk of sanitary sewer overflows (SSOs). Reducing I&I
is an ongoing objective of the District's Capital Improvement Program. The District's treatment
plant operates under Order No. R2-2020-0022, NPDES Permit CA0037851 issued by the Regional
Water Quality Control Board. Reduction of I&I will support compliance with permit conditions.
The John Duckett Basin has been selected for the first assessment under this program. The basin
consists of approximately 163,000 linear feet of gravity sewer tributary to the John Duckett Pump
Station. Pipe lengths are taken from the District's GIS and are approximate; proposers are
responsible for verifying quantities.
2. OBJECTIVE
The District is requesting proposals from qualified firms (Consultants) to design and execute a wet-
weather monitoring program capable of isolating, quantifying, and ranking sources of inflow and
infiltration within the study basin.
The main objectives of this Request for Proposals (RFP) are as follows:
* Measure flow continuously throughout the study basin at a spatial resolution sufficient to
attribute I&I to individual reaches of pipe, rather than only to the basin as a whole.
* Distinguish rainfall-derived inflow from groundwater infiltration and distinguish both from
normal diurnal flow and from flow anomalies caused by blockages or debris.
* Quantify the I&I contribution at each monitored location and rank locations by contribution.
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
* Produce a prioritized list of candidate rehabilitation areas, with the estimated wet-weather
flow reduction associated with each, suitable for direct use in the District's capital
improvement program.
* For each priority area, characterize the probable source type (for example, direct storm
inflow connections, defective manhole covers or structures, mainline pipe defects, or service
lateral infiltration) and identify the category of improvement most likely to reduce the
measured I&I, so that the study results function as a rehabilitation roadmap for the basin.
* Deliver all field data, analysis, and supporting documentation in formats the District can load
into its own GIS and retain permanently.
3. SCOPE OF SERVICES
The District will award a single contract for monitoring and assessment of the entire study basin,
approximately 163,000 linear feet of gravity sewer tributary to the John Duckett Pump Station.
The scope of work shall include the following tasks:
A. Project Setup and Monitoring Plan
* Review the District's GIS, as-built drawings, historical flow records, SSO history, and any prior
I&I work for the basin. The District will provide available data; there is no guarantee that
complete data exists for all facilities.
* Conduct field reconnaissance of candidate monitoring locations, including verification of
access, structure condition, and hydraulic suitability.
* Prepare a monitoring plan with proposed monitoring locations and the sewer segment it is
intended to isolate. The plan shall be delivered as an interactive, web-accessible GIS map and
as a static exhibit and is subject to District review and written approval before installation
begins.
* The monitoring plan shall provide spatial resolution sufficient to attribute measured I&I to
individual reaches of sewer. Proposers shall state the monitoring density they propose,
expressed as monitored locations per mile of pipe, and shall justify that density against the
objectives in Section 2. The District will evaluate proposed density as part of technical
approach.
B. Structure Inspection and Site Preparation
* Inspect each monitored manhole or structure and document its condition. Inspections shall
follow NASSCO MACP standards, or an equivalent standard identified in the proposal.
* Obtain the interior dimensions of each monitored structure to the accuracy required by the
Contractor's flow calculation method. The method used to obtain dimensions (direct
measurement, survey, photogrammetry, laser scanning, or other) is at the Contractor's
discretion, provided the resulting accuracy is documented.
* Provide photographic and/or video documentation of each monitored structure, delivered in
a common, non-proprietary format viewable by District staff without the purchase of
additional software or subscriptions.
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
* All confined space entries shall comply with Cal/OSHA requirements. The Contractor is solely
responsible for the safety of its personnel.
C. Flow Monitoring
* Install and commission monitoring equipment at all approved locations. Installation shall be
complete and all sites verified operational no later than December 1, 2026.
* Monitor continuously, 24 hours per day, 7 days per week, for a period of twenty-four (24)
months, capturing two full winter wet-weather seasons and the intervening dry-weather
seasons, so that storm response, seasonal groundwater infiltration, and year-to-year
variability are characterized. Any proposal to end monitoring before twenty-four (24) months
requires written District approval.
* Record water level at each monitored location at intervals of fifteen (15) minutes or shorter.
Provide telemetry delivering recorded data to a live, web-based dashboard in near real time,
and provide District staff with credentialed access to that dashboard showing sensor status
and current and historical level and calculated flow data at each monitored location, with
user-configurable level alarms, for the duration of the study and following submission of the
final report.
* Maintain the monitoring network throughout the study period, including site visits as
necessary to clear fouling, replace failed equipment, and verify calibration. The Contractor
shall achieve a minimum data completeness of 90% at each monitored site over the
monitoring period. Sites falling below this threshold may, at the District's discretion, be
subject to extended monitoring at no additional cost.
* Obtain and incorporate rainfall data covering the study basin for the full monitoring period, at
a temporal resolution sufficient to correlate individual storm events to measured hydraulic
response. Identify the source of rainfall data and the location of gauges in the proposal.
* Remove all equipment and restore all sites following completion of monitoring. State
separately in the fee proposal any cost adjustment associated with District crews performing
equipment retrieval.
D. Analysis and Reporting
* Convert measured data to flow values, including the hydraulic assumptions, the treatment of
surcharged conditions, and the estimated accuracy.
* Classify the flow at each monitored location, distinguishing at minimum: normal diurnal flow;
rainfall-derived inflow; groundwater infiltration; and anomalies attributable to blockage,
debris, or other obstruction.
* Quantify I&I at each monitored location and rank all locations within the basin by I&I
contribution. Report results using industry-recognized metrics, including at minimum peak
wet-weather flow, peaking factor, and rainfall-derived inflow and infiltration volume per
storm event.
* Identify any location where measured behavior suggests a defect requiring immediate District
attention, and notify the District in writing within five (5) working days of identification
rather than holding the finding for the final report.
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
* Prepare a prioritized list of candidate rehabilitation areas, with estimated recoverable wet-
weather flow for each, ordered so that the District can allocate rehabilitation funding from the
top of the list downward.
* For each priority rehabilitation area, identify the probable I&I source type and recommend
the category of corrective work (for example, mainline lining or replacement, service lateral
rehabilitation, manhole rehabilitation or sealing, or removal of direct inflow sources),
together with any confirmatory investigation (smoke testing, dyed-water testing, or CCTV
inspection) recommended to pinpoint specific defects before design.
* Submit an interim technical memorandum no later than June 15 following each winter wet-
weather season (June 15, 2027 and June 15, 2028), summarizing wet-season findings,
preliminary location rankings, and any early rehabilitation candidates, so that the District can
begin scoping improvements before the full monitoring period concludes.
* Submit a draft report for District review, and a final report incorporating District comments.
* Present findings to District staff and, if requested, to the District Board of Directors. Include
one staff presentation and one Board presentation in the base fee.
E. Deliverables and Data Rights
* All spatial deliverables shall be provided in a format directly compatible with the District's
GIS, including feature classes with populated attribute tables. Static PDF and image files alone
are not acceptable as the sole spatial deliverable.
* All raw measurement data (timestamped level, flow, and rainfall records) shall be delivered to
the District in a non-proprietary, machine-readable format such as CSV.
* The District shall receive a perpetual, irrevocable, royalty-free right to use, reproduce, and
distribute all data, reports, models, imagery, and other deliverables produced under this
contract, including the right to provide them to other consultants and contractors working on
District facilities. Contractors relying on patented or proprietary methods retain rights in
those methods; this provision applies to the deliverables and underlying data, not to the
Contractor's underlying technology.
* Deliverables shall not be conditioned on the District maintaining an ongoing software
subscription. Any subscription required to access deliverables after the contract term shall be
disclosed and separately priced.
F. Other Tasks
* Obtain all permits required by agencies having jurisdiction. Permit fees shall be identified
separately in the fee proposal.
* Prepare traffic control plans for agency review and approval, and provide signs, barricades,
flaggers, and all other equipment and labor as necessary. The Contractor is responsible for
identifying all locations requiring traffic control. Price traffic control separately, and state any
cost reduction available if District crews assist.
* Coordinate with the District regarding access to manholes located in back yards, easements,
and other restricted locations. The District will assist with property owner notification and
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
access coordination; the Contractor shall provide reasonable advance notice of required
access.
* Coordinate with District staff, District consultants, and other agencies as necessary
throughout the study.
G. District-Furnished Items
The District will provide the following. Proposers shall identify any additional District support they
are assuming, so that it can be evaluated as part of the proposal.
* Available GIS data, as-built drawings, and system mapping for the study basin.
* Available historical flow, pump run-time, and SSO records.
* Assistance with property owner notification and coordination of access to restricted
manholes.
General: All records (project reports, meeting notes, data files, project data, calculations, electronic
files, and similar materials) generated under this engagement shall be the property of the District
and shall be turned over to the District upon completion or as directed.
4. PROPOSAL REQUIREMENTS AND CONTENTS
The proposal shall be prepared in accordance with the following. Material submitted in addition to
that specifically required will not be reviewed.
Cover Letter
Include firm name, contact person, and a brief statement of interest describing why the firm is a
good fit.
Firm Overview
Describe the firm's history, size, affiliation(s), and core areas of expertise. Identify any contractor's
license, certifications, or professional registrations applicable to the work.
Relevant Project Experience
Submit three (3) reference projects for comparable I&I assessment work completed within the last
ten (10) years, each with the client name and current contact information, scope, dollar value,
dates, and the firm's role.
Key Personnel
Provide the organizational chart for the contractor team and identify proposed subcontractors, if
any, and their specific tasks. Identify the project manager who will serve as the primary contact
person to the District.
Resumes
Provide the resumes for key staff for the project.
Technical Approach
This section is the primary basis for technical evaluation. At minimum, address:
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
* The monitoring technology proposed, and the proposed monitoring density expressed as
locations per mile.
* The method by which measured data is converted to flow, and the expected accuracy of the
resulting values.
* The method by which inflow is distinguished from infiltration, and by which I&I is separated
from normal diurnal flow and from blockage-related anomalies.
* QA/QC procedures, how data completeness is measured and maintained, and how gaps in the
record are handled in the analysis.
* A preliminary project schedule demonstrating that sensors will be installed and operating by
December 1, 2026.
* If any part of the proposed approach relies on patented or proprietary methods, identify them
so the District can evaluate long-term data access and the deliverable and data rights
requirements of Section 3.E.
Scope of Work (Separate Attachment)
Provide the proposed scope of work as a standalone attachment or on separate pages within the
proposal. It shall be complete in itself, without cross-references to other portions of the proposal,
and formatted so the District can incorporate it directly as an exhibit to the Consultant Agreement.
Fee Schedule (Separate Attachment)
Provide the fee schedule as a standalone attachment or on separate pages, suitable for direct
incorporation as the compensation exhibit to the Consultant Agreement. Include:
* A fee summary by task and a total not-to-exceed amount for the entire study basin.
* Unit prices for optional or additional work: traffic control (per day), extended monitoring
beyond twenty-four (24) months (per month), and additional monitoring locations (each).
* A proposed milestone payment schedule. The District will not make payment for work not yet
performed.
* All conditions under which charges beyond the proposed fee would apply. Charges not
disclosed in the proposal will not be accepted after award.
Exceptions to the Standard Agreement
List any requested exceptions to the District's standard Contractor Agreement, including any
conflict between the firm's standard terms and conditions and the District's Agreement. Exceptions
not raised in the proposal will be deemed waived. Submission of a firm's standard terms and
conditions without identifying the specific conflicts does not satisfy this requirement.
Public Records
Proposals submitted to the District are subject to the California Public Records Act. Proposers who
believe portions of their submittal are exempt from disclosure shall clearly mark those portions and
identify the legal basis for the exemption. Blanket designations covering an entire proposal will not
be honored.
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
5. CONSULTANT SELECTION PROCESS
The criteria used in evaluating proposals include, but are not limited to, the following:
Evaluation Criterion
Knowledge and understanding of the project requirements and District needs
Technical approach, including demonstrated ability to isolate and quantify I&I
Experience on comparable projects and quality of references
Responsiveness and ability to perform within the established schedule
Commitment of key personnel and their experience
6. TENTATIVE CONSULTANT SELECTION AND PROJECT SCHEDULE
Milestone Date
Request for Proposals Published September 8, 2026
Questions on the RFP Deadline SSeepptteemmbbeerr 91,5 2, 0220626
Proposal Deadline September 22, 2026 at 2:00 PM
Award of Contract October 1, 2026
Notice to Proceed Within five (5) days of award
Monitoring Plan Approved by District November 9, 2026
All Sites Installed and Operational December 1, 2026
Monitoring Period December 2026 through November
2028
Interim Wet-Season Technical Memoranda June 15, 2027 and June 15, 2028
Equipment Removal and Site Restoration December 2028
Draft Report Within 45 days of equipment removal
Final Report and Presentation Within 30 days of receipt of District
comments
Responses to all questions received will be issued by addendum to all firms that have received this
RFP. Verbal responses are not binding on the District.
7. STANDARD CONSULTANT AGREEMENT
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
The Contractor selected to provide the Scope of Services shall use the District's standard Consultant
Agreement (attached). By submitting a proposal for this work, the Contractor agrees to use this
form for the contract, subject only to exceptions identified in the proposal. Contractually required
insurance coverage and endorsement information is set forth in the body of the Agreement and its
exhibits.
8. ATTACHMENTS
* Attachment 1 - District Standard Contractor Agreement
* Attachment 2 - Study Basin Map
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LAS GALLINAS VALLEY SANITARY DISTRICT RFP - Sanitary Sewer Inflow and Infiltration Assessment
Attachment 1: District Standard Contractor Agreement
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