- Standard Design Criteria
- Procedure for Dedication of
Easement to Castro Valley Sanitary District
- Sewage Pumping System Requirements
- Procedure for Sewage Pump Approval and Installation
- Pumping System Information
- General Provisions and Specifications
Standard Design Criteria
Pipe Type
- Vitrified Clay Pipe (VCP) may be used:
- on all gravity public collector sewers and building sewers (laterals).
- where pipe cover is greater than four (4) feet in all areas.
- where pipe slope is less than 20%.
- Ductile Iron Pipe (DIP) or Cast Iron Pipe (CIP) must be used:
- where pipe cover is less than four (4) feet in areas subject to vehicular loadings.
- where pipe cover is not less than two (2) feet in areas not subject to vehicular loadings.
- 3) when pipe slope is greater than 20% upon written authorization by the District.
- in special circumstances, as required by the District.
- High Density Polyethylene (HDPE – SDR 17), Color Black may
be used:
- on building sewers subject to District Code and Specifications.
- on all residential forced main systems.
- where cover for building sewers is greater than four (4) feet in areas subject to vehicular loadings.
- where cover for building sewers is greater than two (2) feet in areas not subject to vehicular loadings.
- where pipe slope is less than 20%.
- High Density Polyethylene (HDPE – SDR 17), Color Grey may
be used:
- only when the manufactured date, heat stamped on the pipe, is less than one (1) year old.
- on building sewers subject to District Code and Specifications.
- on all residential forced main systems.
- on all public sanitary sewer mains where cover is greater than four (4) feet in all areas.
- when pipe slope is less than 20%.
- 8" diameter minimum for public (District maintained) collector sewers.
- 4" diameter minimum for individual gravity building sewer (lateral).
- 4” diameter minimum for conventional pump residential force main system.
- 2” diameter minimum for grinder pump residential force main system.
Pipe Slope
The following minimum pipe slopes and the maximum pipe slope of 20% shall
not be exceeded without specific written authorization by the District.
- 8" mains at 1.0% minimum.
- 6" laterals at 2.0% minimum.
- 4" laterals at 2.0% minimum.
- Larger sizes: design for nominal velocity of 2½ fps flowing
half-full.
- Soils reports will be required on hillsides and creek areas where:
- Slopes of hills where sewers are proposed for installation exceeding twenty (20) percent.
- Sewers are proposed for installation within fifty (50) feet of creek beds.
- Sewers are proposed for installation within the range of influence of a possible landslide from adjacent hill.
- Sewers are proposed for installation in historic slide locations.
- A soils report shall be prepared and submitted by a registered civil
engineer practicing in Geotechnical Engineering, covering the proposed
project.
- If the project geotechnical report provided does not cover an off-road
sewer alignment, the District may require a supplementary report.
This report, at a minimum, must address the following:
- Supplementary geological setting, general soils and bedrock condition along the proposed sewer alignment, and recommended set backs from slides and creeks.
- Stability or instability of selected sewer alignment.
- Potential ground water problems.
- Effect of trenching on slope stability (negative impacts on slope).
- Special backfill, special trenching requirements, or special supports (such as cut-off walls) may be recommended.
- Erosion potential of soils around sewer near water courses.
- Recommended correction if an instability exists or may develop.
- If, in the sole determination of the District, it is unfeasible
to locate sewer mains on the downside slope of future homes and maintain
a safe distance from drainage ways, consideration will be given to
installing the sewers in street areas which may result in the installation
of a pump system. The project engineer is to provide the District
with a feasibility study describing various methods which could be
used to serve the proposed development including gravity (in streets
and easements), publicly maintained sewage pump station and residential
sewage pumps on individual homes.
- An access easement, minimum width of fifteen (15) feet, shall be granted by the Developer from the nearest public street to any sanitary sewer facilities such as manholes or pump stations.
- The access easement shall be graded at a slope not to exceed four (4) percent to allow ingress and egress with conventional sanitary sewer cleaning equipment, such as a class “B” vehicle.
- A ten (10) foot radius area around manholes shall be level sloping slightly away.
- The access easement may be paved or gravel surfaced.
- The access easement may be in addition to an easement at the alignment of the proposed sewer.
Structures
Manholes to be placed:
- at 300 foot nominal spacing.
- at all junctions of collector sewers.
- at all ends of sewer mains, except stubs for future extensions with no lateral connections.
- at all changes of pipe size.
- as otherwise required by the District.
- Match crowns at change of pipe size.
- Install velocity head loss at all changes of direction:
- Loss = V²/2g x Deflection/90º, (0.25' minimum).
- Use straight grade between manholes where possible.
- Curvilinear alignment (vertical and horizontal, or in combination) to be minimum 300’ radius, accomplished by deflection at pipe joints, within pipe manufacturer's recommendations.
- Locate sewers on street centerline, except where specified otherwise by Alameda County Public Works Department.
- Avoid easements wherever possible. If in roadway, the easement is to be the entire width of paved section.
- 10' width absolute minimum when not in roadway.
- Center pipe in easement.
- Easements along rear lot lines are especially undesirable. If unavoidable, the District may require an all-weather road over the pipe for maintenance access.
- Avoid manholes on private property.
- All work (public or private) to be in accordance with District Standard Specifications.
- For sewer service to less than four lots, use 4" diameter pipe laterals in a common trench rather than a collector sewer (except where further extension of the sewer can be anticipated). Minimum width of 12" clear separation between two laterals in a common trench.
- Drop manholes are not permitted; manhole base should have a 1/2” through fall.
Procedure for Dedication
of Easement to Castro Valley Sanitary District
- Grantor's Engineer prepares legal description of easement (metes
and bounds), which becomes "Exhibit A" to the Grant of Easement
document, and a plat showing location of easement.
- Description checked for accuracy by District staff.
- Grantor submits description and plat to a title company of their
choice and orders preliminary title report covering easement area
to be sent to the District.
- District staff reviews preliminary report and advises grantor of
any liens reflected in preliminary report which must be subordinated
to priority of proposed easement. In general, any security interest
created by deeds of trust, leases, or other forms of property conveyance
must be junior and subordinate to District easements. The District's
standard subordination form is to be used.
- Easements must be dedicated on the District's standard Grant of
Easement form by the person(s) holding fee title to the property the
easement will cross. Grant and subordination documents, if required,
must be executed before a notary and shall contain an acknowledgment
of the notary. If a document is executed by persons acting for corporations,
the corporate seal must be affixed to the document unless the corporation
by-laws specifically state such seal is not necessary.
- Following receipt of properly executed documents, they shall be
presented to the District Board for acceptance at a regular or special
meeting of the Board. In order to be placed on the agenda for such
meeting, all required documents should be received in the District
Office at least one week prior to the meeting date.
- Following acceptance by the Board, District staff shall submit all documents into the previously established escrow with instructions to record all documents and to issue a policy of title insurance to the District in a face amount to be determined by the District. Generally, this will be the minimum amount written by the title company, which is currently $25,000. Grantor is responsible for all title fees and recording fees, if any.
Sewage Pumping System Requirements
All design and installation shall be done in conformance with the general requirements of the Cal OSHA, current applicable electrical and building codes, and Castro Valley Sanitary District (District) requirements.
The minimum requirements for a residential sewage pumping system connecting a single residence (or equivalent) to the District’s system are specified in the following paragraphs. The District accepts no responsibility for the design, operation, or maintenance of such privately owned and operated systems.
All equipment and accessories shall be standard manufactured items, and those coming in direct contact with sewage shall be specifically manufactured for sewage use by a company regularly engaged in the manufacturing and assembly of similar units for a minimum of five (5) years. Manufacturer specifications for pump systems, including electrical controllers, sumps, etc., shall be submitted to the District for review and approval prior to the start of any work.
Residential installations require dual pumps (duplex system) if static head is greater than 25 feet and/or greater than 150 feet in length. Otherwise, single pump installations may be used. It is recommended that dual pumps be used in all residential installations.
For uses other than residential, per Section 710.9 of the Uniform Plumbing Code, installations require dual pumps (duplex system) designed to function independently in case of overload or mechanical failure.
Unless otherwise approved, the pump(s) shall be one of the three types described below:
- Centrifugal, non-clog, vertical column with enclosed shaft.
- Submersible, centrifugal, non–clog, rated as explosion proof, designed for Class 1, Group D, Division 1 hazardous locations. The pump shall carry the Underwriters Laboratories label for this use.
- Submersible, centrifugal, grinder pump, rated as explosion proof, designed for Class 1, Group D, Division 1 hazardous locations. The pump shall carry the Underwriters Laboratories label for this use.
If pump types 1) or 2) are used, the pumps shall have a capacity of 45 GPM when pumping against the required head at LWL without surcharge. The impeller shall be a non-clog type and shall be capable of passing a 2-inch sphere. The minimum pump discharge shall be 4 inches in diameter.
If a submersible grinder pump is used, the pump shall have a capacity of 16 GPM when pumping against the required head at LWL without surcharge for a pump discharge of 2 inches in diameter. The grinder shall be constructed of long-lasting, low-maintenance material that is capable of reducing all components in normal domestic sewage (including a reasonable amount of “foreign objects,” such as paper, wood, plastic, glass, rubber, etc.) to finely divided particles which will pass freely through the passages of the pump.
For installations with dual pumps (duplex system), an alternator shall be provided to automatically sequence the starting of the lead and lag pumps on each operating cycle so that each pump is assured of equal operation time.
The sump shall be cylindrical in configuration with a minimum diameter of 36 inches, and shall have a minimum distance of 16 inches between the HWL and LWL and a maximum distance of 24 inches between the HWL and LWL or a special approval is required for a distance not in the specified range. The pump sump inlet invert shall be 6 inches above the HWL.
The pump sump shall be made of one of the following materials:
- Asphalt-coated steel (prefabricated 3/16-inch steel plate).
- Fiberglass.
All fiberglass tanks shall be filament wound, minimum ¼ - inch wall thickness with tank interior surface protected with a minimum 0.10-inch thick, resin-rich, corrosion barrier and shall have anti-flotation flanges if the tank is 200 gallons or larger in capacity.- High Density Polyethylene.
The pump sump shall be provided with a 4-inch minimum inlet stub and an outlet stub (if located on sump) the size of the pump discharge.
The pump sump cover shall not be less then ½ - inch epoxy coated steel plate or heavy cast iron made to accommodate the pump (if a column type) with an opening for the electrical conduits, vent, and an inspection plate. The cover shall be designed to resist the maximum dead and live loads, including impact (H-2O required for traffic areas).
The sump cover shall be securely anchored to the pump sump by stainless steel bolts, and all joints between the component parts shall be sealed with gasketed covers that are gas tight.
Motors for column-type pumps shall be a drip-proof vertical type, shall be totally enclosed weather protected, and shall conform to the standards of NEMA.
Submersible pump motors for explosion proof pumps shall be constructed with the windings operating in a sealed air-filled environment, with thermal overload protection. Any lubricants used such as oil shall be FDA approved. There shall be a moisture-sensing probe in the inner-seal chamber to detect moisture and warn of impending outer-seal failure. The motor shall conform to the standards of NEMA as to the enclosure, type of mounting, and basic electric design.
The pump’s level controls shall be the ball and rod mechanical float or solid core mercury switches sealed within polypropylene shell(s) with neoprene covered cable, or an approved equal. High water set point shall not be less than six (6) inches below invert of inlet pipe into the pump tank, and a high water alarm shall be set above the high water set point.
For nonexplosion-proof submersible pumps, the level control for the low water set point shall be positioned so that the motor is fully submerged at all times. A redundant low water pump level control shall be mounted below the low water pump level control and shall de-energize power to the pump in both the manual and automatic modes. Each pump level control shall be wired directly and independently to terminals within the control panel.
The level control and all alarm system circuits shall be listed by the Underwriters Laboratory as intrinsically safe. The circuits shall reduce the power to the pilot devices and alarms to a value incapable of releasing sufficient thermal or electrical energy to ignite a hazardous environment.
The alarm system shall be mounted within the building that is served by the pump and shall provide a visible pilot light, and an audible alarm with silencer to alert the occupant. The alarm system shall be on a separate circuit from the pump motor. A high water alarm system shall be provided for a high water condition. A low water level alarm system shall be required only for non-explosion rated submersible pumps to ensure the pump is never exposed during draw down. The alarm system shall remain latched should the high water or low water condition occur until cleared by the occupant.
The panel shall be mounted external to the pump tank. The panel shall have a NEMA I classification when mounted inside the building served or a NEMA 4X enclosure when mounted outside the building served.
All electrical work shall conform to the requirements of Alameda County, and/or the District, whichever in the opinion of the District Engineer is the most stringent. Power requirements shall be as recommended and approved by Pacific Gas and Electric Company.
The installation of a high water overflow pipe is optional. If installed, the pipe shall be the same size as the discharge line and shall extend to an area where the sewage can be collected and disposed of. A check valve shall be installed in the line to keep foreign objects from entering the system.
The sump shall be vented by a two (2) inch or larger diameter vent extended to a point ten (10) feet above the sump cover with a return bend at top of vent.
The pressure potion of the discharge line, including the gate valve, check valve, cleanout and mechanical couplings, shall be equal in size to the pump discharge. The discharge line connecting the check valve, gate valve, cleanout and mechanical couplings shall be as per the District’s Code and Standard Specification for forced mains. The remaining discharge line to the gravity portion of the private building sewer shall conform to District’s Standard Specifications and shall meet District’s depth and bedding requirements for building sewers.
The gravity potion of the discharge line shall meet the District requirements for building sewers and shall provide a minimum slope of 2% from the junction of the pressure line to the connection with the public sanitary sewer main.
Procedure for Sewage Pump Approval and Installation
Before the Design Phase Begins
- Contact Castro Valley Sanitary District (District) Engineering Department at (510) 537-0757.
- Provide the Engineering Department at the District with sufficient information to determine that a pump is required for sewer service.
- If a sewage pump is required, the Owner of the site shall select a registered professional engineer to design the sewage pumping system
- The registered professional engineering shall contact the Engineer
at the District (510) 537-0757 for an information package.
- The registered professional engineer shall prepare a plot plan for
the site. The plot plan shall have plan and profile with sufficient
information to determine a system curve. The pumping system information
sheet identifies the elevations and distances that are required. The
pressure sewer diameter, type and bedding shall be specified on the
profile. If the pressure sewer will connect to a gravity sewer that
is not a public sewer, pipe diameter, slope, distances and elevations
are required to verify that the gravity sewer has enough capacity
for the flow from the sewage pumping system. The impeller and diameter
shall be specified. Two system curves shall be plotted on the pump
curve. The system curve for the low water level with surcharge head
shall be plotted. The system curve for high water level and no surcharge
head shall be plotted.
- The registered professional engineer shall prepare a sewage pumping
system design to meet District requirements.
- The registered professional engineer shall complete and submit
District’s Standard Specifications, pumping system information
sheets (including pump head calculations), plot plan, pump curve and
catalog cut sheets to show the equipment that will be installed at
the site. Electrical drawings showing the required controls and alarms
shall be submitted for review when a redundant low water pump level
control is required. The registered professional engineer’s
stamp and signature shall be on the submitted information.
- The Engineer at the District will review the submitted information, request additional information, require changes to agree with District’s specifications, or agree that the submitted information conforms to District’s requirements. The District accepts no responsibility for approval on the design of the pump system.
- The Owner shall pay fees and charges.
- The Contractor/Owner shall obtain an appropriate permit.
- The Contractor shall notify District inspection staff at (510) 537-0757, 48 hours prior to starting work.
- The Contractor shall always notify the inspector when he is working.
- Testing procedures on the pump system should conform to District’s Code and Standard Specifications.
- When the work is complete, the Contractor shall arrange for final inspection of the system including the electrical sign off form from the appropriate electrical supplier.
Pumps Approved by the District
- Barnes Pumps, Inc.
- Environment One Corporation
- Goulds Pumps
- Hydromatic
- ITT Flygt Corporation
- F. E. Myers
Pumping System
Information
Profile
and Plan
Sump base elevation ______________________Ft.
Motor top elevation _______________________Ft.
Low alarm elevation _______________________Ft.
Redundant off _____________________Ft.
Pumps off/LWL elevation ___________________Ft.
Lead pump on/HWL elevation _______________Ft.
Lag pump on elevation _______________Ft.
High alarm _________________Ft.
Inlet invert elevation _____________Ft.
Surrounding surface elevation _________________Ft.
Sump cover elevation __________________Ft.
Invert elevation at discharge to atmosphere __________________Ft.
Upstream manhole rim elevation ____________________Ft.
Pressure line distance _____________________Ft.
Centrifugal Pump: Yes _______No______ Impeller size selected_______ Non-Clog Pump: Yes _______ No ______ Grinder Pump: Yes______ No ______ Submersible Pump: Yes______ No ______ Explosion-proof: Yes ____No ____ Redundant Low-level cutoff before pump exposed: Yes ______No ______ Simplex Control System: Yes ______ No ______ Intrinsically safe: Yes ___No____ Duplex Control System: Yes ______ No ______ Intrinsically safe: Yes ___No____ Asphalt-coated steel sump: Yes _____No______ Filament wound fiberglass sump: Yes ____No______ T-lock lined reinforced concrete pipe sump: Yes ______ No ______ Check Valve No._______ 22.5 degree els No.________ Gate/Plug Valve No._______ Wyes No.________ Clean out No._______ Tees No.________ 90 degree els No._______ Reducers No.________ 45 degree els No._______ Increasers No.________
Provide the number of residential units for residential development______________
Provide the number of fixture-units for commercial and residential development_________
Friction Head Calculation (head losses in feet due to flow through pipes, valves, fittings, entrance, and exit head losses, etc.)
Static Head Calculation
Surcharge Head Calculation
TDH (without surcharge)
TDH (with surcharge)
General
Provisions and Specifications
Click here
to view the General Provisions and Specifications for the Construction
of Sanitary Sewers. Please note that these Provisions and Specifications
are for informational purposes only (subject to change) -- for the most
current copy, please contact the District at (510) 537-0757.
Castro Valley Sanitary District
21040 Marshall Street
Castro Valley, CA 94546-6098
Phone: (510) 537-0757 | Fax: (510) 537-1312 | Email: info@cvsan.org