Typical construction durations shown are approximate. Actual duration may vary dependent on existing conditions, site-specific road/traffic conditions, and weather conditions. For updated current information on when construction will occur in your specific area, please contact the Project Engineer, City of Palo Alto, Water, Gas, Wastewater Engineering.
Contractor moves equipment and material near the construction area or to their storage yard. Contractor marks the boundaries of the area for underground Service Alert (USA).
1 - 2 working days
USA / Survey
Underground Service Alert (USA) and City Survey Crew marks out existing utilities and proposed water main alignment on the street pavement with spray paint.
2 - 5 working days
The Contractor sawcuts existing pavement as marked by the survey crew.
1 - 3 working days
The Contractor removes pavement and excavates soil to prepare for installation of a new water main and services.
1 - 3 working days
New Water Main, Services Installation, and Existing Services Reconnection
The Contractor performs a system tie-in to an existing water main, closes tie-in valve, and begins laying new main and service connection points along the new water main alignment. Note: Your service is not connected to the new system at this stage of the construction.
2 - 6 working days
New water main pressure test
To assure tightness at pipe joints and fittings, the Contractor performs hydrostatic pressure tests on the new water main. Water mains are pressurized with potable water using pressure at lowest elevation in the system at 150 psi. The pressure is being maintained constant for 4-hour period by adding makeup water. After 4-hour period is completed, the pressure shall remain steady within 5% (7.5 psi) of a target 150 psi test pressure for one hour.
For a typical city block: 6 to 8 hours
Fill new main with water for disinfection & bacteriological Test
System tie-in valve is opened to fill the installed system with water. A liquid disinfectant (chlorine) is injected into the charged system to kill any pre-existing microbial organisms. The new water main will stay chlorinated for at least 24 hours and then flushed until chlorine concentration decreases to 1ppm. Then water samples will be gathered and taken to a laboratory for analysis. The Contractor will be required to perform two consecutive 24-hours apart bacteriological (Coliform) tests.
Less than 1 hour
Water test results back in 1-2 working days
Service Transfer Connections
Once the Bacteriological Test has passed and written passing results are submitted, the Contractor begins connecting your service line to the new water main.
0.5 - 3 hours per service (this entails an individual water service interruption)
Contractor fills and compacts the ground openings with backfill material as the new main is installed.
Performed concurrently with the new main and services installation and connection
Install Temporary Pavement or "Cutback"
Temporary cold asphalt mix is placed on the backfilled area to temporarily restore the roadway service. If your street is concrete, steel plates will be placed on top of the trench in order for the concrete base to cure, prior to final restoration.
Performed concurrently with the new main and service installation, connection, and backfill
Final Pavement Restoration
The Contractor removes temporary asphalt pavement, steel plates, and restores pavement and all surface improvements to the preconstruction condition
1 - 3 days per block
The Contractor sweeps the street affected by the project and removes USA markings.
1 - 2 days per block
New water main connection to existing water distribution system
New Water mains will be tied into water distribution system within 24 hours following the acceptance of the bacteriological tests' results.
Utilities Operations Office Municipal Service Center 3201 East Bayshore Rd. Palo Alto, CA 94303 Electric Phone: 650-496-6934 Fax: 650-493-8427 Water, Gas, Wastewater Phone: 650-496-6982 Fax: 650-496-6924 Hours: Mon-Fri 7:00-3:30pm