The Michigan Department of Public Health is authorized
by Act 399, P.A. 1976, as amended, to promulgate rules necessary
to continuously provide safe and adequate supply of water to the
users of public water supply systems. The water supply cross connection
rules were initially formulated under Act 98, P.A. 1913, with
an effective date of April 19, 1972. The rules have been carried
over and now are set forth under Act 399, P.A. 1976. The water
utility has been named as the agency responsible for development
of a local program which when fully implemented will eliminate
all cross connections to public water supply systems. It is not
necessary that the water utility actually be the inspection or
enforcement agency. This function may be performed by the water
utility, the plumbing inspection bureau, the local health department,
or any combination of the three. The staff of the Michigan Department
of Public Health will provide technical assistance and training
to local personnel and will assist the local enforcement agency
with any difficult problems which may arise.
The rules are meant to support any existing cross
connection program, including programs which may now be in effect
under the state plumbing law (Act 266, Public Acts of 1929, as
amended), state plumbing code, and local codes. These rules enable
the water utility to work hand in hand with the state and local
plumbing agencies in requiring strict adherence to good plumbing
and public health practices.
The rules provide water utilities a legal basis
for reviewing (or have another agency review) their customers'
water systems for cross connections. They also allow requirements
which adequately protect the public water supply system whenever
a potential hazard is discovered. The Michigan Department of
Public Health recommends the rules be adopted by local ordinance
to assist local enforcement. A suggested model ordinance is included
in the appendix of this manual for information and guidance in
drafting a local ordinance.
A matter of importance to industries, commercial establishments, water utilities, plumbing inspection agencies, and health agencies is the continued supply of potable water for consumers within an industrial, commercial, or other establishment. All state and local plumbing codes should be carefully and completely enforced by the responsible agencies to protect the inplant system from all potential cross connections. The Michigan Occupational Safety and Health Administration (OSHA) also is concerned about the hazard of cross connections from the standpoint of employee safety.
Rule 325.11404 of the Administrative Rules under
Act 399 requires a municipal water supply to develop a comprehensive
control program for the elimination and prevention of all cross
connections. The plan for the program was to be submitted to
the Michigan Department of Public Health for review and approval
by January 11, 1979. Once the plan is approved, the water
must begin implementing the program for removal of all existing
cross connections and prevention of all future cross connections.
A model program and program outline are included in the appendix
14.6.1 Local Ordinance - Enforcement Agency
The local authority for implementation of the program
shall be indicated, preferably by ordinance (See appendix for
model ordinance). The program must designate a local inspection
and enforcement agency or agencies which shall be one or more
of the following: the water utility, the plumbing inspection
agency, the local health department.
14.6.2 Schedule of Inspections
A time schedule shall be proposed for the inspection of all water utility customers' premises for possible cross connections. It is suggested that the initial schedule of inspections be arranged so that the most critical establishments will be inspected as soon as possible, with a schedule for inspection of those less hazardous installations to follow. This would necessitate listing the industrial commercial, and other establishments where cross connections are deemed most probable. A schedule for the reinspection of all cross connections must be outlined and carried out to make certain that acceptable means of protection are in place and in working order.
Again, the criteria for determining the time interval
between inspections are based upon the potential hazards involved.
These criteria should be outlined in the proposed program. The
recommendations of the Department of Public Health on this subject
are included later in this manual. Inspection and reinspection
schedules and procedures are absolutely necessary in initiating
and maintaining a satisfactory cross connection control program.
Reference should be made to the appendix for suggested recordkeeping
formats for initial inspections, reinspections, and results of
testing backflow prevention devices.
14.6.3 Testing of Devices
Experience has shown that there is not a mechanical
device which can be depended on unless it is routinely checked,
tested, and maintained. Backflow prevention devices should be
tested only by a qualified individual who is knowledgeable of
the workings of backflow prevention devices and fully realizes
the hazards of cross connections with a potable water supply system.
It is recommended that all reduced pressure zone backflow preventers
be tested initially upon installation and at yearly
intervals thereafter. It may be justifiable to call for more
or less frequent testing of a device depending on specific circumstances
such as quality of water passing through the device, atmosphere
corrosiveness, type of hazard involved, etc. As a minimum, all
reduced pressure principle backflow preventers shall be tested
at least every five (5) years.
In an effort to achieve uniform testing throughout
the state, periodic training courses will be sponsored to train
qualified individuals to test reduced pressure principle backflow
preventers. Such courses have been conducted in the past by the
Michigan Health and Safety Institute, and more recently, by the
Michigan Plumbing and Mechanical Contractors Association. The
courses have been sanctioned by the Plumbing Division, Michigan
Department of Labor, the State Plumbing Board, and the Division
of Water Supply, Michigan Department of Public Health. These
and future training courses will be open to plumbing contractors,
plumbing inspectors, and water utility personnel involved with
cross connection control.
If the inspection agency plans to provide the service
of testing all mechanical devices, it would seem reasonable and
appropriate to charge for expenses incurred for testing. A more
viable alternative is authorization of certain trained personnel,
such as qualified plumbing contractors, to perform tests. This
approach would likely be more practical in the event repairs or
replacement work is needed on the device or other plumbing fixtures
since this work by law demands performance by a licensed plumber.
Signed reports from the authorized inspector would indicate that
the device(s) had been tested and whether or not it was in satisfactory
condition. Whichever method is utilized, the inspection agency
must make certain that all required information is gathered and
retained. (See appendix for suggested record-keeping format.)
14.6.4 Protective Devices
Section 14.3 discussed cross connection protective
devices. Included in the appendix is a list of approved mechanical
devices by name, model, number, and size. This list is updated
and distributed periodically, with the most recent list available
upon request from the Michigan Department of Public Health. It
must be clear to all users that cross connection protection measures
must be in accordance with the local approved
and/or this manual if they are to be considered adequate. Any
variations proposed should be submitted to and approved by the
Michigan Department of Public Health prior to installation.
14.6.5 Time for Correction
The time allowed for completion of necessary corrections
shall be contingent upon: (1) the degree of hazard involved,
and; (2) the time required to obtain and install equipment. If
the cross connection has not been removed after a reasonable period
of time, the water utility shall physically separate the public
water supply from the on-site
piping system in such a manner that the two systems cannot again
be connected by any unauthorized person. This is required by
rule. If an extremely hazardous situation is discovered, it may
be reasonable to consider immediate separation of the two systems.
When such a condition is encountered, the local inspection agency
should contact the Department of Public Health to discuss the
matter before requiring the immediate separation of the two systems.
14.6.6 Recordkeeping and Annual Report
The rules require that the water utility report annually to the Michigan Department of Public Health concerning the status of the local cross connection control program. Report forms are made available each year by the department. The information required is quite general in nature in order to keep the paperwork to a minimum. At the same time, it must be stressed and understood by all concerned that complete and accurate reports and records are necessary and must be maintained by the water utility and/or the local inspection agency. These records should include the name of user, the type of hazard involved, the locations within the plant with existing and potential cross connections, the type of protection required for the cross connection, the location of required protective devices, the dates, results, and findings of each inspection and reinspection, and the status of the methods and protective devices installed. Records should also include names of persons contacted during visits, persons who should be contacted in the future, etc. (See appendix for suggested recordkeeping formats.)
The primary responsibility of the water utility
through the cross connection rules is to protect the public water
supply distribution system against the entrance of contaminants.
In many cases, the only practical way to assure complete protection
of the public water supply is by service line protection. When
a utility is faced with a customer whose internal piping system
is difficult to follow or is subject to frequent and unauthorized
change, service line protection or "containment" of
the premises may be necessary.
In many other instances, it may be possible to provide
adequate protection of the public water supply by Installing protective
devices throughout the premises at the points where cross connections
are located. Such action, called "isolation" provides
protection for not only the public water supply, but for the internal
plant potable water supply as well.
Premises which may typically dictate containment
include plating industries, hospitals, automotive plants, carwashes,
complexes with secondary water supplies, chemical plants, sewage
treatment plants, and laboratory buildings. Services which may
adequately be protected by isolation of the problem area(s) may
include churches, schools, restaurants, and those industrial or
commercial premises which have easily distinguishable and simplified
It is essential that a safe and adequate supply
of water be made available to all consumers within an industry
when the public water supply is protected by a device installed
at the service. In some instances, it may be possible to utilize
a small service line for potable use with the tap made on the
protected side of the protection device. This might be acceptable
in relatively small (less complex) installations where it would
be possible to completely separate the line for potable use from
all other internal plumbing and where the line for potable use
only is easily identifiable by being accessible and plainly marked.
If this is not done or if the internal system is extensive and
complex, it will normally be necessary to duplicate the protective
device required for installation on the public water supply service
line. If it is certain that the potable supply line is free from
cross connections and the enforcement agency carefully monitors
this in their reinspection program, it may be possible to permit
the installation of a protective device which provides a somewhat
lesser degree of protection on the potable supply line than that
required on the plant service. If such a program is to be considered,
it must be discussed in detail in the local program and must be
approved by the Michigan Department of Public Health.
If the in-plant system is contained, i.e., the public
supply is protected by a suitable device installed at the service,
all outlets (hose bibbs, etc.) on the industrialized system should
be clearly marked -- "Nonpotable."
The following tables outline recommended procedures
for protecting against certain general types of cross connection
conditions that may be encountered. These tables are to be used
as guidelines in determining adequate cross connection control
measures. Whenever a unique cross
connection piping arrangement is encountered which may not be
covered clearly by these tables, utilities should consult the
Michigan Department of Public Health for assistance or clarification.
14.8.1 Secondary Water Supplies
1) Reduced pressure principle backflow preventer.
2) See Sec. 14.4.1 for classification of wells.
14.8.2 Submerged Inlet or Connection into Pipes or Tanks
All state and local plumbing codes
must be strictly enforced to protect interior piping systems
carrying potable water.
1 --A safe air-gap arrangement should be created in the water supply line(s) to problem area(s) or in the service line downstream from the meter.
2 --Reduced pressure principle backflow preventer.
3 --Refer to discussion in manual for proper selection and installation of vacuum breakers. These devices are adequate against backsiphonage conditions only.
4 --Many types of water cooled refrigeration systems exist. Water supply lines to some types need full protection whereas other types may require only air-gapping the discharge line into a drain. Consult MDPH for assistance whenever necessary.
5 --The main concern with a conventional water softener is the waste discharge line. As a minimum, the waste line must be air-gapped into a drain. If full protection is provided, an air-gap, reduced pressure principle backflow preventer, or pressure-type vacuum breaker should be installed on the water inlet line.
6 --Minimum protection required shall be a stainless steel double check valve with intermediate vent.
7 --These means of protection are consistent with the requirements of the state plumbing code. Low pressure untreated boilers are required by the state plumbing code to have a double check valve assembly or equivalent protection.
The following list includes those types of water
customers which historically have posed a threat to public health
because of piping systems that have been cross connected with
a potable water supply. This listing is
as an aid to water utilities to determine which customers may
be jeopardizing the public water supply. The list is by no means
complete for all utilities in that each supply may have its own
unique type of customer that may pose a public health threat.
A. Automotive, manufacturing plants
B. Chemical, plating, processing plants
C. Breweries, bottling plants
D. Canneries, packing houses, meat processing operations
E. Dairy processing operations
F. Photographic developing laboratories
G. Research laboratories
II. Commercial Establishments, etc.
A. Hospitals, medical buildings, sanitariums, nursing homes, convalescent homes, clinics
B. Mortuaries, morgues, funeral homes
C. Refrigeration or cold storage plants
D. Laundries, dry cleaning operations
E. Car washes
F. Grain elevators
G. Restaurants, taverns
H. Beauty salons
III. Other Customers
A. Schools, churches
B. Parks, DPW facilities
C. Golf courses (lawn sprinkling systems)
D. Cemeteries (lawn sprinkling systems)
E. Sewage treatment plants, sewage lift stations
F. Water treatment plants
G. Private-homes with wells, swimming pools, lawn sprinkling systems
H. Apartment complexes
In light of the complexity of many industrial and
commercial piping systems and the likelihood of piping modifications
occurring from time to time, reinspection must be carried out
of those water customers where cross connections were previously
found or where cross connections may be created. In many instances
where service line protection is provided, reinspection can be
conducted at the time of meter reading. In other instances where
in-house protection is provided, reinspections must be purposely
scheduled to check each area of concern. Particular attention
must always be given to assure that protective devices have not
been bypassed or made ineffective in any way.
The suggested reinspection timetable below applies
basically to determining that the protective devices are properly
in place where needed and that there are no obvious malfunctions.
As previously discussed in Section 14.6.3, testing of the backflow
prevention device (RPPBP) should be carried out according to local
Because of the complexity of many industrial piping
systems, pipe color coding is extremely useful as a means to identify
and segregate potable and non-potable piping systems. Consequently,
many utilities should seriously consider incorporating on file
a color code scheme which local industries can reference.
Proposed variations within the community can be
submitted to the local enforcement agency and approved if satisfactory.
Any variations from the recommended local code must be filed
with the local agency. It is recommended that charts be posted
throughout the plant to notify personnel of the code in use.
Tags can be used in place of color coding if a user so desires
and if the local enforcement agency approves.
The following is a color coding scheme for piping
systems as recommended by the Great Lakes Upper Mississippi River
Board of State Sanitary Engineers. This is strictly an example
and can be adopted or changed as desired by the local agency.
Raw --------------------========-------------Olive Green
Settled or Clarified ----------------------------Aqua
Finished or Potable ---------------------------Dark
Alum or Primary Coagulant ------------------Orange
Carbon Slurry ----------------------------------Black
Caustic Soda -----------------------------------Yellow with Green Band
Chlorine (gas & solution) -------------------Yellow
Coagulant Aids or Polymers--------------- Orange with Green Band
Fluoride Light ----------------------------------Blue with Red Band
Lime Slurry -------------------------------------Light Green
Ozone -------------------------------------------Yellow with Orange Band
Phosphate Compounds ----------------------Light Green with Red Band
Potassium Permanganate---------------------- Violet
Soda Ash -----------------------------------------Light Green with Orange Band
Sulfur Dioxide -----------------------------------Light Green with Yellow Band
Yellow with Red Band
Backwash Waste------------------------------ Light Brown
Sludge-------------------------------------------- Dark Brown
Sewer (sanitary or other)-------------------- Dark Gray
Compressed Air--------------------------------Dark Green
Gas (natural, liquid, or diesel fuel)-------- Red
Other Lines------------------------------------- Light Gray