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 utility 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 for reference.

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 program 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 piping systems.

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 included 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.

I. Industries

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

I. Greenhouses

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 governing criteria.

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.

Water Lines

Raw --------------------========-------------Olive Green

Settled or Clarified ----------------------------Aqua

Finished or Potable ---------------------------Dark Blue

Chemical Lines

Alum or Primary Coagulant ------------------Orange

Ammonia ----------------------------------------White

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

Sulfuric Acid------------------------------------ Yellow with Red Band

Waste Lines

Backwash Waste------------------------------ Light Brown

Sludge-------------------------------------------- Dark Brown

Sewer (sanitary or other)-------------------- Dark Gray

Other

Compressed Air--------------------------------Dark Green

Gas (natural, liquid, or diesel fuel)-------- Red

Other Lines------------------------------------- Light Gray