III. WATER SYSTEM GENERAL DESIGN STANDARDS
A. Water Distribution System Basis of Design
1.
A water distribution system basis of design shall be submitted with
construction plans for approval by the Livingston Community Water
Authority Engineer. The basis of design shall include an area map
indicating the areas and zoning district for each area to be served,
including any off-site areas. The basis of design will reflect proposed
developmental phasing.
2.
In general, water distribution systems shall be designed in accordance
with the Recommended Standards for Water Works b the Great LakesUpper Mississippi River Board of State Public Health and Environmental
Managers (“Ten State Standards”), Michigan Department of
Environmental Quality (MDEQ) Regulations, and this design standard
document.
3.
Residential developments shall consider a design population of at least
2.6 persons per dwelling unit with an average daily water demand of 100
gallons per capita per day (gpcd). A residential equivalent unit (REU) is
equal to 260 gpd.
In non-residential developments, flow estimates shall be based on water
use records from similar facilities, as may be provided by petitioner and
approved by the Livingston Community Water Authority Engineer, or an
estimate of proposed water demand in accordance with the respective
Township’s Residential Equivalent User (REU) Schedule having
jurisdiction.
4.
For the purpose of network analysis and water main design, maximum
daily demands will be computed as no less than twice the average daily
demand. Peak hourly flows will be computed as no less than 3 times the
average daily demand.
5.
Water main shall be designed to provide fire protection (rates and
durations) based on the requirements of the local Fire Department and
recommendations of the Insurance Services Office (ISO) for projected
land use and building types, but shall be no less than the following
minimum standards:
Land Use/Building Type
Residential and Multi-Family
Commercial
Industrial
6.
Minimum Fire Protection Rate
1,500 gpm for 2 hours
2,500 gpm for 2 hours
3,500 gpm for 3 hours
Water main shall be sized to meet peak hourly demands and to meet
maximum daily demands plus fire protection rates. The petitioner shall
provide a Basis of Design to the LCWA Engineer (via the Township
Engineer) so the domestic water demand and the required minimum fire
protection rate can be incorporated into the LCWA water model. The
LCWA Engineer will determine if the existing system has sufficient
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capacity or if system-wide improvements are needed to facilitate the
proposed development.
7.
Distribution mains shall be 8-inch minimum diameter. Transmission
mains of 12-inch diameter and larger may be required if future
development plans dictate such sizing.
B. Water Main Layout
1.
All sites developing an on-site water main network shall be serviced by
two water main connections to the existing water system or shall be
planned for service from an adjacent site by extending the water main to
one or more property lines.
All water mains shall be carried to the limits of the development for future
extension by neighboring properties. Water mains must be extended
across the entire frontage on any existing public streets and roads that
the proposed development fronts upon. Water main in excess of 1,600
lineal feet between interconnections may be required to be oversized at
the petitioner’s expense. The LCWA may also require, at the Authority’s
expense, that any water main in the system be oversized.
2.
Dead-end mains may not exceed 600 feet in a single-family, residential
neighborhood or 500 feet in a multiple-family, residential neighborhood.
3.
Hydrants shall be a maximum of 500 feet on center from each other in
residential, commercial and industrial areas. Additional hydrants may be
required at locations selected by the local Fire Department.
4.
Buildings shall be covered within a 250-foot radius of a hydrant and within
no more than 400 feet of hose laid to any part of the structure. In singlefamily, residential areas, the hydrant coverage may be increased to 350foot radius with the approval of the local Fire Department and the LCWA
Engineer. The radii of coverage may be reduced in industrial area at the
discretion of the local Fire Department.
5.
Valves shall be placed at each junction of water main and in such a way
that no more than three valves have to be closed to isolate a branch of
water main and no more than two hydrants will be affected. Valves for
use on 8-inch diameter mains and smaller shall be in valve boxes. Valves
on water mains greater than 8-inch diameter shall be provided in a gate
well unless valve boxes are otherwise approved by the LCWA Engineer.
6.
Valves 16 inch and smaller shall be resilient-seated gate valves meeting
the requirements of Section 15110 of the Technical Specifications.
Valves that are greater than 16 inch shall be butterfly valves meeting the
requirements of Section 15110 of the Technical Specifications.
7.
All unnecessary utility crossings shall be avoided. A minimum 10-foot
horizontal and 18-inch vertical clearance shall be maintained from
sanitary and storm sewers. Water main shall be placed no closer than 20
feet from any building footing.
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8.
Water main shall be placed in the public right-of-way or private road
easement where possible. Water main may be placed in easements if
approved by the LCWA Engineer. Where placement in easements is
approved, a minimum 25-foot-wide permanent easement is required
unless a variance is approved by the LCWA Engineer. Based on the site
condition, additional easement width may be required as determined by
the LCWA Engineer. The easement must be maintained as accessible
to LCWA personnel and equipment for maintenance and repair. The
water main shall be centered in the easement.
C. Depth of Water Main
Water main shall be placed with a minimum of 5.5 and maximum of 7.5 feet of
cover over the pipe. Where water main is installed in undeveloped areas or
areas subject to future grading, probable finished grades will be considered. If
water main is constructed in areas where pavement will be constructed in the
future, granular backfill shall be used.
D. Joint Restraint
All water main shall be designed with mechanical restraint of joints in accordance
with Standard Technical Specifications and Details. Concrete thrust blocks are
not permissible except when constructing an anchor-ring for HDPE pipe (see W10), when placing a tapping sleeve and valve in a well (see W-6D) or as
approved by the LCWA Engineer.
E. Back Flow Prevention
All connections, except residential property owners are required to have backflow
preventers on their water services. RPZ backflow preventers are required for
high hazard connections where medical or chemical processes occur. Other low
hazard connections will require a double check valve assembly. Fire lines require
backflow preventers.
F. Service Leads
1.
Each building shall have its own service lead extending from the main line
to the building. Service leads shall be 1-inch diameter minimum for
residential properties and 2- inch diameter minimum for commercial
properties and be installed at a depth of not less than 5.5 feet. Leads
shall be provided with a shutoff valve at the property line or easement
line. The portion of the lead located between the main and the shutoff
valve shall be considered public and shall be type K for services less than
4-inch. Class 52 ductile iron pipe with polyethylene wrap or HDPE
services (if approved by the LCWA Engineer) shall be used for services
greater than 4-inch in diameter. The material of the privately owned
portion of the service lead shall be coordinated with the Building
Department of the appropriate Township.
2.
For buildings served with a large diameter fire suppression line, the
domestic service may be tapped off the fire line outside the structure.
The fire suppression line and the domestic service shall be provided with
shutoff valves that are independent of each other. An easement shall be
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provided from the property line to the shutoff valves for access by the
Water Authority.
G. Meters
1.
All buildings using LCWA water shall be metered. In general, water
meters shall be placed in basements, utility rooms, or mechanical rooms.
When necessary, meters may be placed in a well-drained meter pit upon
approval of the LCWA Engineer. Accessibility to the meters shall be
maintained at all times.
2.
The water meter, meter horn, touchpad and MXU shall be obtained from
the LCWA. The water meter shall be a Sensus positive displacement
meter with a touchpad and an MXU (for radio read capabilities). The
touchpad shall be mounted 36 inches above the finish grade elevation on
the exterior wall of the building. The water meter for all single-family,
residential dwelling units shall be a minimum size of ¾ inch. The size
shall be determined by the petitioner’s engineer and approved by the
LCWA Engineer for non-residential meters.
3.
Fire lines (4-inch diameter or greater) may bypass the meter, provided the
fire system is alarmed in accordance with the Michigan Building Code and
the National Fire Protection Association latest editions.
4.
Calculations for limited area sprinklers system shall be presented as a
hydraulically calculated model rather than pipe schedule when the fire
flow passes through the meter.
H. Irrigation Well Separation
For existing sites serviced by wells permitted through the Livingston County
Health Department, the property owner may retain the use of the well for
irrigation purposes only provided the following:
1.
The existing well(s) are properly permitted through the Livingston County
Health Department.
2.
The LCWA cross connection control program policy must be adhered to.
3.
Prior to connecting to the public water source, the existing well system
must be completely isolated from the piping system by way of a physical
separation of pipe, or air gap. The separation requirements must meet all
applicable local, state and national rules, regulations and guidelines.
4.
The well isolation shall be verified by physical inspection performed by
the local plumbing inspector and a representative of LCWA. This shall be
handled through an application for a plumbing permit through the
township having jurisdiction.
5.
All existing wells that are not properly permitted through the Livingston
County Health Department shall be properly abandoned.
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6.
I.
Once served by public water, new or replacement irrigation wells will not
be permitted.
Well Abandonment
1.
The work shall be completed by a water well drilling contractor registered
in the State of Michigan, who shall comply with all applicable rules,
regulations, and guidelines published by the State of Michigan regarding
the performance of the work. Upon completion of the work, the water well
drilling contractor shall notify the Livingston County Health Department of
the well abandonment.
2.
The water well drilling contractor shall comply with Act 53, PA of 1974, by
notifying the public utilities of the proposed drilling or excavating at least
72 hours prior to the commencement of such activities by contacting
MISS DIG at 1-800-482-7171.
J. Connection of an Existing Subdivision to the LCWA Water System
In the event that LCWA water is extended to an existing subdivision served by a
community well, connection of the subdivision to the LCWA water system shall
be in accordance with the LCWA Roles and Responsibilities.
K. Pumping Facilities
1.
Pumping facilities must be designed in accordance with Recommended
Standards for Water Works, latest edition as well as Suggested Practice
for Water Works Design, Construction and Operation for Type I Public
Water Supplies, MDEQ Water Bureau, latest edition.
2.
Pumping facilities shall be above grade stations. No underground
facilities will be accepted.
3.
The pumping facility shall have the capacity of meeting maximum day
water demand with the largest pump out of service provided there is
sufficient storage to supplement peak hour and fire protection demands.
If storage is insufficient for peak hour and fire protection demands, then
the pumping facility must be capable of meeting the peak hour and fire
demands of the area served.
4.
Pumping facilities will be provided with SCADA to allow for remote
monitoring and operation of the station. SCADA must be installed and
integrated with the existing LCWA system. If the existing SCADA system
needs to be upgraded to accommodate the proposed system, that
upgrade shall be paid for by the applicant.
5.
Pumping facilities whose failure would result in less than 35 psi normal
operating pressure and less than 20 psi under peak demand (and fire)
conditions must be equipped with an emergency power supply.
6.
Pumping facilities will become part of the overall LCWA water system.
L. Township Meter Vaults
Individual Township meter vaults will not be required. All LCWA customers will
be metered either individually or through a subdivision or complex master meter.
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M. Storage Tanks
1.
Storage tanks must be designed in accordance with Recommended
Standards for Water Works, latest edition as well as Suggested Practice
for Water Works Design, Construction and Operation for Type I Public
Water Supplies, MDEQ Water Bureau, latest edition.
2.
Storage tanks can be elevated or ground level.
3.
Elevated storage tanks should be designed with the ability to add
communication antennas in the future.
4.
Sizing of storage tanks must consider peak water demand, fire fighting
requirements, water stagnation, control of ice formation, etc.
5.
New storage tanks will become part of the overall LCWA water system
and must be able to hydraulically work with the existing system.
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