Idaho Admin. Code r. 58.01.08.501 - FACILITY AND DESIGN STANDARDS: GENERAL DESIGN REQUIREMENTS FOR PUBLIC DRINKING WATER SYSTEMS

Unless otherwise specified by the Department, the design of new drinking water systems, or modifications to existing, public drinking water systems, shall be in conformance with the facility and design standards set forth in Sections 006 and 500 through 552 of these rules. The following general design requirements shall apply as applicable for the type of water system and the treatment or other processes employed. (3-24-22)

01. Materials Used in Construction. Products that are used to construct public drinking water systems and have water contact surfaces shall conform to applicable AWWA standards and be certified by an accredited ANSI certification body to meet applicable ANSI/NSF standards, where products meeting such AWWA and ANSI/NSF standards exist. In the absence of such products, products meeting applicable product standards and acceptable to the reviewing authority may be selected. Corrosion control shall be taken into account during all aspects of public water system design. (3-24-22)

02. Additives Used in Operation. No chemical or other substance shall be added to drinking water, nor shall any process be utilized to treat drinking water, unless specifically approved by the Department. All chemicals shall conform to applicable AWWA standards and be certified by an accredited ANSI certification body to meet ANSI/NSF Standard 60, referenced in Subsection 002.02. (3-24-22)

03. Design Basis. The system, including the water source and treatment facilities, shall be designed to provide either peak hour demand of the system or maximum day demand plus equalization storage at the design year. (3-24-22)

04. Design of Treatment Facilities. Design of treatment facilities shall address: (3-24-22)

a. Functional aspects of facility layout and provisions for future facility expansion; (3-24-22)

b. Provision for expansion of waste treatment and disposal facilities (see Section 540) ; (3-24-22)

c. Roads constructed to provide year-round access by vehicles and equipment needed for repair and maintenance; (3-24-22)

d. Site grading and drainage; and (3-24-22)

e. Chemical Feed or Injection. Unless otherwise approved by the Department based on documentation provided by the design engineer, all chemical feed or injection systems must be designed to ensure complete mixing through rapid mix devices or other measures. (3-24-22)

f. Redundancy. Unless otherwise approved by the Department or as specified in other sections of these rules, to ensure that minimum quality, quantity, and pressure requirements of these rules are continuously met during maintenance, breakdowns, structural failures, emergencies, or other periods when components must be out of service, water system treatment, filtration, and disinfection components for all new or substantially modified community or nontransient, noncommunity drinking water systems shall be designed such that plant design capacity can be maintained with any component out of service. Raw water intake structures are excluded from the general redundancy requirement but shall be designed to ensure that plant design capacity will be maintained. (3-24-22)

05. Design of Buildings. The design of buildings that are a part of public drinking water systems shall provide for: (3-24-22)

a. Adequate ventilation, lighting, heating, and air conditioning; (3-24-22)

b. Adequate drainage; (3-24-22)

c. Dehumidification equipment, if necessary; (3-24-22)

d. Accessibility of equipment for operation, servicing, and removal; (3-24-22)

e. Flexibility and convenience of operation and safety of operators; and (3-24-22)

f. Separate room(s) for chemical storage and feed equipment that may be required based on type of chemicals and associated hazards. (3-24-22)

06. Electrical. Main switch gear electrical controls shall be located above grade, in areas not subject to flooding. All electrical work shall conform to the requirements of the National Electrical Code or to relevant state/ local codes. The National Electrical Code is available from the National Fire Protection Association, 1 Batterymarch Park, Quincy, Massachusetts 02169-7471, (617)770-3000, http://www.nfpa.org. (3-24-22)

07. Reliability and Emergency Operation. New community water systems constructed after April 15, 2007 are required to have sufficient dedicated on-site standby power, with automatic switch-over capability, or standby storage so that water may be treated and supplied to pressurize the entire distribution system during power outages. During a power outage, the water system shall be able to meet the operating pressure requirements of Subsection 552.01.b. for a minimum of eight (8) hours at average day demand plus fire flow where provided. A minimum of eight (8) hours of fuel storage shall be located on site unless an equivalent plan is authorized by the Department. Standby power provided in a public drinking water system shall be coordinated with the standby power that is provided in the wastewater collection and treatment system. (3-24-22)

a. The Department may require the installation of standby power or storage facilities in existing systems if the frequency and duration of power outages a system experiences constitute a health hazard. (3-24-22)

b. Existing community public water systems that are substantially modified after April 15, 2007 shall meet the requirements of Subsection 501.07. in those portions of the system affected by the modifications. (3-24-22)

c. New sources and booster pumps intended to increase system capacity shall be provided with standby power or equivalent unless, during a power outage, the public water system or distribution system pressure zone can already meet the minimum operating capacity and pressure requirements in Subsection 501.07 for a minimum of eight (8) hours at average day demand plus fire flow where provided for each pressure zone. (3-24-22)

d. For both new and existing public water systems, the Department may reduce the requirements of Subsection 501.07 if the system can demonstrate the capacity to adequately protect public health during a power outage. Any decision by the Department will be based on, but not limited to, the following considerations: (3-24-22)

i. An adequate emergency response and operation plan and the capacity to implement that plan. (3-24-22)

ii. The adequacy of the system's cross connection control program and the capacity to protect public health in the event of a system wide depressurization. (3-24-22)

iii. Demonstration of historical and projected reliability of the electrical power supplied to the water system. (3-24-22)

iv. A strategy for providing information to the public during power outages, including instructions to stop irrigation, boil water, etc., until notified otherwise. (3-24-22)

v. The level of reliability acceptable to consumers. This can be accomplished with either a vote of the majority of consumers for privately owned and operated systems or a decision by the governing body for publicly governed systems. (3-24-22)

vi. Other considerations that may be pertinent, including connections to other public water systems, agreements to provide water in emergency situations, and the availability of dedicated portable auxiliary power. (3-24-22)

08. On-Site Analysis and Testing Capabilities. Each public water system shall have equipment and facilities for routine testing necessary to ensure proper operation. Equipment selection shall be based on the characteristics of the raw water source and the complexity of the treatment process involved. (3-24-22)

09. Sample Taps. Sample taps shall be provided so that water samples can be obtained from each water source and from appropriate locations in each unit operation of treatment, and from the finished water. Taps shall be consistent with sampling needs and shall not be of the petcock type. Taps owned by the water system and used for obtaining samples for bacteriological analysis shall be of the smooth-nosed type without interior or exterior threads, shall not be of the mixing type, and shall not have a screen, aerator, or other such appurtenance. (3-24-22)

10. Facility Potable Water Supply. The facility water supply service line and the plant finished water sample tap shall be supplied from a source of finished water at a point where all chemicals have been thoroughly mixed, and the required disinfectant contact time, if applicable, has been achieved. There shall be no cross connections between the facility water supply service line and any piping, troughs, tanks, or other treatment units containing wastewater, treatment chemicals, raw or partially treated water. (3-24-22)

11. Meters. All water supplies shall have an acceptable means of measuring the flow from each source, the wash water, the recycled water, any blended water of different quality, and the finished water. (3-24-22)

12. Operation and Maintenance Manual. A new or updated operation and maintenance manual that addresses all water system facilities shall be submitted to the Department for review and approval prior to start-up of the new or materially modified public water system unless the same system components are already covered in an existing operation and maintenance manual. For existing systems with continual operational problems as determined by the Department, the Department may require that an operation and maintenance manual be submitted to the Department for review and approval. The operator shall ensure that the system is operated in accordance with the approved operation and maintenance manual. (3-24-22)

13. Start-Up Training. Provisions shall be made for operator instruction at the start-up of a new plant or pumping station. (3-24-22)

14. Safety. Consideration shall be given to the protection of maintenance personnel and visitors from typical and foreseeable hazards in accordance with the engineering standards of care. The design shall comply with all applicable safety codes and regulations that may include the Uniform Building Code, International Fire Code, National Fire Protection Association Standards, and state and federal OSHA standards. Items to be considered include, but are not limited to, noise arresters, noise protection, confined space entry, protective equipment and clothing, gas masks, safety showers and eye washes, handrails and guards, warning signs, smoke detectors, toxic gas detectors and fire extinguishers. (3-24-22)

15. Security. Appropriate design measures to help ensure the security of water system facilities shall be incorporated. Such measures, at a minimum, shall include means to lock all exterior doorways, windows, gates and other entrances to source, treatment, pumping stations, and water storage facilities. (3-24-22)

16. Other Regulations. Consideration must be given to the design requirements of other federal, state, and local regulatory agencies for items such as safety requirements, special designs for the handicapped, plumbing and electrical codes, and construction in the flood plain. (3-24-22)

17. Ground Water Source Redundancy. New community water systems served by ground water shall have a minimum of two (2) sources if they are intended to serve more than twenty-five (25) connections or equivalent dwelling units (EDUs). Under normal operating conditions, with any source out of service, the remaining source(s) shall be capable of providing either the peak hour demand of the system or a minimum of the maximum day demand plus equalization storage. See Subsection 501.18 for general design and redundancy requirements concerning fire flow capacity. (3-24-22)

18. Redundant Fire Flow Capacity. (3-24-22)

a. Public water systems that provide fire flow shall be designed to provide maximum day demand plus fire flow. Fire flow requirements and system adequacy shall be determined by the local fire authority or by a hydraulic analysis by a licensed professional engineer to establish required fire flows in accordance with the International Fire Code as adopted by the State Fire Marshal. Pumping systems supporting fire flow capacity must be designed so that fire flow may be provided with any pump out of service. (3-24-22)

b. The requirement for redundant pumping capacity specified in Subsection 501.18.a. may be reduced to the extent that fire suppression storage is provided in sufficient quantity to meet some or all of fire flow demands. Where fire suppression storage is not provided, the requirement for fire flow pumping redundancy may be reduced or eliminated if the following conditions are met: (3-24-22)

i. The local fire authority justifies that the fire flow capacity of the system is acceptable and is compatible with the water demand of existing and planned fire-fighting equipment and fire-fighting practices in the area served by the system. (3-24-22)

ii. In a manner appropriate to the system type and situation, notification is provided to customers that describes the design of the system's fire-fighting capability and explains how it differs from the requirements of Subsection 501.18.a. (3-24-22)

19. Pilot Studies. Unless otherwise approved by the Department based on documentation provided by the design engineer, pilot studies are required for treatment processes other than chlorine disinfection or point of use installations. Pilot studies may be performed in the field using the proposed source water or in conjunction with bench scale testing in the lab using the proposed source water. The system shall obtain the Department's approval of a pilot study plan before the pilot study is implemented. A pilot study shall be conducted for a period that shall be determined by the design engineer and approved by the Department. A final pilot study report with results shall be submitted to the Department for review and approval. Upon completion of the pilot study, final approval of equipment and treatment processes is subject to the applicable requirements of Sections 500 through 552. (3-24-22)

a. Pilot Study Plan. A pilot study plan shall include the following and any other items required by the Department: (3-24-22)

i. Introduction and Background. The plan shall discuss general information about the project including the existing system, the reason for conducting the pilot study, and anticipated results of a successful pilot study. (3-24-22)

ii. Alternative Processes. Provide a brief description of alternative processes that could be used if the proposed process is shown to be ineffective from the study. (3-24-22)

iii. Procedures and Methods. The procedures and methods section shall discuss how the pilot study will be conducted, the time frame of the study, source water quality, how source water may be altered to mimic various source water quality conditions, and the water quality parameters that are monitored and evaluated to determine if the treatment process was effective. (3-24-22)

b. Pilot Study Report. The pilot study report shall include the following and any other items required by the Department: (3-24-22)

i. Introduction and Background. (3-24-22)

ii. Results. A discussion of the overall pilot study progress, including any issues or problems and a general discussion of results of the study and what the results indicate. This discussion should determine parameters necessary for full scale implementation. (3-24-22)

iii. Conclusions. Conclusions and recommendation to proceed with the treatment process if the results of the study proved successful. (3-24-22)

c. Additional specific pilot study requirements in Sections 500 through 552 shall be included in pilot study plans and reports. (3-24-22)

d. Engineer's Seal Required. Pilot study plans and pilot study reports submitted to the Department shall bear the imprint of an Idaho licensed professional engineer's seal that is both signed and dated by the engineer. (3-24-22)

Notes

Idaho Admin. Code r. 58.01.08.501