1. (a) General Provisions. The following requirements are to be used in evaluating both the total capacities for public water systems and the capacities at individual pump stations and pressure planes. The capacities listed below are minimum requirements only. Additional supply, storage, service pumping, and pressure maintenance facilities will be required by the commission if a normal operating pressure of 35 psi cannot be maintained throughout the system, or if the system's maximum daily demand exceeds its total production and treatment capacity. Additional capacities will also be required if the system is unable to maintain a minimum pressure of 20 psi during fire fighting, line flushing and other unusual conditions. In all sections governing quantity requirements, total storage capacity does not include pressure tank capacity.

2. (b) Community Water Systems.

   1. (1) Groundwater supply requirements are as follows:

      1. (A) If fewer than 50 connections without ground storage, the system must have the following:

         1. (i) a well capacity of 1.5 gallons per minute per connection; and
         2. (ii) a pressure tank capacity of 50 gallons per connection.

      2. (B) If fewer than 50 connections with ground storage, the system must have the following:

         1. (i) a well capacity of 0.6 gallon per minute per connection;
         2. (ii) a total storage capacity of 200 gallons per connection;
         3. (iii) two or more service pumps having a total capacity of 2.0 gallons per minute per connection; and
         4. (iv) a pressure tank capacity of 20 gallons per connection.

      3. (C) For 50 to 250 connections, the system must meet the following requirements:

         1. (i) A well capacity of 0.6 gallon per minute per connection must be provided.
         2. (ii) A total storage capacity of 200 gallons per connection must be provided.
         3. (iii) Each pump station or pressure plane shall have two or more pumps having a total capacity of 2.0 gallons per minute per connection. For systems which provide an elevated storage capacity of 200 gallons per connection, two service pumps with a minimum combined capacity of 0.6 gallons per minute per connection are required at each pump station or pressure plane. If only wells and elevated storage are provided, service pumps are not required.
         4. (iv) An elevated storage capacity of 100 gallons per connection or a pressure tank capacity of 20 gallons per connection must be provided.

      4. (D) For more than 250 connections, the system must meet the following requirements:

         1. (i) Two or more wells having a total capacity of 0.6 gallons per minute per connection must be provided. Where an interconnection is provided with another acceptable water system capable of supplying at least 0.35 gallons per minute for each connection in the combined system under emergency conditions, an additional well will not be required as long as the 0.6 gallons per minute per connection requirement is met for each system on an individual basis. Each water system must still meet the storage and pressure maintenance requirements on an individual basis unless the interconnection is permanently open; in this case, the systems' capacities will be rated as though a single system existed.
         2. (ii) A total storage capacity of 200 gallons per connection must be provided.
         3. (iii) Each pump station or pressure plane shall have two or more pumps that have a total capacity of 2.0 gallons per minute per connection or that have a total capacity of at least 1,000 gallons per minute and the ability to meet peak hourly demands with the largest pump out of service, whichever is less. For systems which provide an elevated storage capacity of 200 gallons per connection, two service pumps with a minimum combined capacity of 0.6 gallons per minute per connection are required at each pump station or pressure plane. If only wells and elevated storage are provided, service pumps are not required.
         4. (iv) An elevated storage capacity of 100 gallons per connection or a pressure tank capacity of 20 gallons per connection must be provided. If pressure tanks are used, a maximum capacity of 30,000 gallons is sufficient for up to 2,500 connections. An elevated storage capacity of 100 gallons per connection is required for systems with more than 2,500 connections. Alternate methods of pressure maintenance may be proposed and will be approved if the criteria contained in §290.45(g)(2) of this chapter are met.
         5. (v) Emergency power is required for systems which serve more than 250 connections and do not meet the elevated storage requirement. Sufficient emergency power must be provided to deliver a minimum of 0.35 gallons per minute per connection to the distribution system in the event of the loss of normal power supply. Alternately, an emergency interconnection can be provided with another public water system that has emergency power and is able to supply at least 0.35 gallons per minute for each connection in the combined system. Emergency power facilities in systems serving 1,000 connections or greater must be serviced and maintained in accordance with level 2 maintenance requirements contained in the current NFPA 110 standards. Although not required, compliance with NFPA 110 standards is highly recommended for systems serving less than 1,000 connections. Logs of all emergency power use and maintenance must be maintained and kept on file for a period of not less than three years. These records must be made available, upon request, for commission review.

      5. (E) Mobile home parks with a density of 8 or more units per acre and apartment complexes which supply fewer than 100 connections without ground storage must have the following:

         1. (i) a well capacity of 1.0 gallon per minute per connection; and
         2. (ii) a pressure tank capacity of 50 gallons per connection with a maximum of 2,500 gallons required.

      6. (F) Mobile home parks and apartment complexes which supply 100 connections or greater, or fewer than 100 connections and utilize ground storage must meet the following requirements:

         1. (i) A well capacity of 0.6 gallons per minute per connection must be provided. Systems with 250 or more connections must have either two wells or an approved interconnection which is capable of supplying at least 0.35 gallons per minute for each connection in the combined system.
         2. (ii) A total storage of 200 gallons per connection must be provided.
         3. (iii) At least two service pumps with a total capacity of 2.0 gallons per minute per connection must be provided.
         4. (iv) A pressure tank capacity of 20 gallons per connection must be provided.

   2. (2) All surface water supplies must provide the following:

      1. (A) a raw water pump capacity of 0.6 gallon per minute per connection with the largest pump out of service.
      2. (B) a treatment plant capacity of 0.6 gallon per minute per connection under normal rated design flow.
      3. (C) transfer pumps (where applicable) with a capacity of 0.6 gallon per minute per connection with the largest pump out of service.
      4. (D) a covered clearwell storage capacity at the treatment plant of 50 gallons per connection or, for systems serving more than 250 connections, 5.0% of daily plant capacity.
      5. (E) a total storage capacity of 200 gallons per connection.
      6. (F) a service pump capacity that provides each pump station or pressure plane with two or more pumps that have a total capacity of 2.0 gallons per minute per connection or that have a total capacity of at least 1,000 gallons per minute and the ability to meet peak hourly demands with the largest pump out of service, whichever is less. For systems which provide an elevated storage capacity of 200 gallons per connection, two service pumps with a minimum combined capacity of 0.6 gallons per minute per connection are required at each pump station or pressure plane.
      7. (G) An elevated storage capacity of 100 gallons per connection or a pressure tank capacity of 20 gallons per connection must be provided. If pressure tanks are used, a maximum capacity of 30,000 gallons is sufficient for systems of up to 2,500 connections. An elevated storage capacity of 100 gallons per connection is required for systems with more than 2,500 connections. Alternate methods of pressure maintenance may be proposed and will be approved if the criteria contained in §290.45(g)(2) of this chapter are met.
      8. (H) Emergency power is required for systems which serve more than 250 connections and do not meet the elevated storage requirement. Sufficient emergency power must be provided to deliver a minimum of 0.35 gallons per minute per connection to the distribution system in the event of the loss of normal power supply. Alternately, an emergency interconnection can be provided with another public water system that has emergency power and is able to supply at least 0.35 gallons per minute for each connection in the combined system. Emergency power facilities in systems serving 1,000 connections or greater must be serviced and maintained in accordance with level 2 maintenance requirements contained in the current NFPA 110 standards. Although not required, compliance with NFPA 110 standards is highly recommended for systems serving less than 1,000 connections. Logs of all emergency power use and maintenance must be maintained and kept on file for a period of not less than three years. These records must be made available, upon request, for commission review.

3. (c) Noncommunity water systems serving transient accommodation units. The following water quantity requirements apply to noncommunity water systems serving accommodation units such as hotel rooms, motel rooms, travel trailer spaces, campsites and similar accommodations.

   1. (1) Ground water supply requirements are as follows:

      1. (A) If fewer than 100 accommodation units without ground storage, the system must have the following:

         1. (i) a well capacity of 1.0 gallon per minute per unit; and
         2. (ii) a pressure tank capacity of 10 gallons per unit with a minimum of 220 gallons.

      2. (B) For systems serving fewer than 100 accommodation units with ground storage or serving 100 or more accommodation units, the system must have the following:

         1. (i) a well capacity of 0.6 gallons per minute per unit;
         2. (ii) a ground storage capacity of 35 gallons per unit;
         3. (iii) two or more service pumps which have a total capacity of 1.0 gallon per minute per unit; and
         4. (iv) a pressure tank capacity of 10 gallons per unit.

   2. (2) All surface water supplies, regardless of size, must have the following:

      1. (A) a raw water pump capacity of 0.6 gallons per minute per unit with the largest pump out of service;
      2. (B) a treatment plant capacity of 0.6 gallons per minute per unit;
      3. (C) a transfer pump capacity (where applicable) of 0.6 gallons per minute per unit with the largest pump out of service;
      4. (D) a ground storage capacity of 35 gallons per unit with a minimum of 1,000 gallons as clearwell capacity;
      5. (E) two or more service pumps with a total capacity of 1.0 gallon per minute per unit; and
      6. (F) a pressure tank capacity of 10 gallons per unit with a minimum requirement of 220 gallons.

4. (d) Noncommunity water systems serving other than transient accommodation units.

   1. (1) The following table is applicable to paragraphs (2) and (3) of this subsection and shall be used to determine the maximum daily demand for the various types of facilities listed:
      Attached Graphic
      

   2. (2) Groundwater supply requirements are as follows.

      1. (A) If fewer than 300 persons per day are served, the system must have the following:

         1. (i) a well capacity which can supply the maximum daily demand of the system during the hours of operation; and
         2. (ii) a minimum pressure tank capacity of 220 gallons with additional capacity, if necessary, based on a sanitary survey conducted by the commission.

      2. (B) If 300 or more persons per day are served, the system must have the following:

         1. (i) a well capacity which can supply the maximum daily demand;
         2. (ii) a ground storage capacity which is equal to 50% of the maximum daily demand;
         3. (iii) if the maximum daily demand is less than 15 gpm, at least one service pump with a capacity of three times the maximum daily demand must be provided;
         4. (iv) if the maximum daily demand is 15 gpm or more, at least two service pumps with a total capacity of three times the maximum daily demand; and
         5. (v) a minimum pressure tank capacity of 220 gallons with additional capacity, if necessary, based on a sanitary survey conducted by the executive director.

   3. (3) Each surface water supply or groundwater supply that is under the direct influence of surface water, regardless of size, shall meet the following requirements:

      1. (A) a raw water pump capacity which can meet the maximum daily demand of the system with the largest pump out of service;
      2. (B) a treatment plant capacity which can meet the system's maximum daily demand;
      3. (C) a transfer pump capacity (where applicable) sufficient to meet the maximum daily demand with the largest pump out of service;
      4. (D) a clearwell capacity which is equal to 50% of the maximum daily demand;
      5. (E) two or more service pumps with a total capacity of three times the maximum daily demand; and
      6. (F) a minimum pressure tank capacity of 220 gallons with additional capacity, if necessary, based on a sanitary survey conducted by the commission.

5. (e) Water wholesalers. The following additional requirements apply to systems which supply wholesale treated water to other public water supplies.

   1. (1) All wholesalers must provide enough production, treatment and service pumping capacity to meet or exceed the combined maximum daily commitments specified in their various contractual obligations.
   2. (2) For systems supplying both retail and wholesale connections, the commission's production, treatment and service pumping capacity requirements for the system's wholesale connections are in addition to the commission's requirements for the system's retail connections.
   3. (3) Emergency power is required for each portion of the system which supplies more than 250 connections under direct pressure and does not provide an elevated storage capacity of at least 100 gallons per connection. If emergency power is required, it must be sufficient to deliver 20% of the minimum required service pump capacity in the event of the loss of normal power supply. When the wholesaler provides water through an air gap into the purchaser's storage facilities it will be the purchaser's responsibility to meet all minimum water system capacity requirements including emergency power.

6. (f) Purchased water systems. The following requirements apply only to systems which purchase treated water to meet all or part of their production, storage, service pump, or pressure maintenance capacity requirements.

   1. (1) The water purchase contract shall be available to the commission in order that production, storage, service pump, or pressure maintenance capacity may be properly evaluated. For purposes of this section, a contract may be defined as a signed written document of specific terms agreeable to the water purchaser and the water wholesaler, or in its absence, a memorandum or letter of understanding between the water purchaser and the water wholesaler.
   2. (2) The contract shall authorize the purchase of enough water to meet the monthly or annual needs of the purchaser.
   3. (3) The contract shall also establish the maximum rate at which water may be drafted on a daily and hourly basis. In the absence of specific maximum daily or maximum hourly rates in the contract, a uniform purchase rate for the contract period will be used.
   4. (4) The maximum authorized daily purchase rate specified in the contract plus the actual production capacity of the system shall be at least 0.6 gallons per minute per connection.
   5. (5) For systems which purchase water under direct pressure, the maximum hourly purchase authorized by the contract plus the actual service pump capacity of the system must be at least 2.0 gallons per minute per connection or provide at least 1,000 gallons per minute and be able to meet peak hourly demands, whichever is less.
   6. (6) All other minimum capacity requirements specified in this section shall apply.

7. (g) Alternative capacity requirements. Public water systems may request approval to meet alternative capacity requirements in lieu of the minimum capacity requirements specified in this section. Any water system requesting to use an alternative capacity requirement must demonstrate to the satisfaction of the executive director that approving the request will not compromise the public health or result in a degradation of service or water quality as specified in §290.39(l) of this title (relating to General Provisions).

   1. (1) Alternative capacity requirement for public water systems may be granted upon request to and approval by the executive director. The request to use an alternative capacity requirement must include:

      1. (A) Provision of a detailed inventory of the major production, pressurization, and storage facilities utilized by the system.
      2. (B) Provision of records kept by the water system that document the daily production of the system. The period reviewed shall not be less than three years. The applicant may not use a calculated peak daily demand.
      3. (C) The executive director may also require data acquired during the last drought period in the region.
      4. (D) The peak demand days over the study period must utilize data on the number of active connections to determine the actual demand per connection experienced.
      5. (E) Description of any unusual demands on the system such as fire flows or major main breaks that will invalidate unusual peak demands experienced in the study period.
      6. (F) Any other relevant data needed to determine that the proposed alternative capacity requirement will provide a level of service that is equivalent to the level of service provided by the minimum capacity requirements contained in this section.

   2. (2) Although elevated storage is the preferred method of pressure maintenance for systems of over 2500 connections, it is recognized that local conditions may dictate the use of alternate methods utilizing hydropneumatic tanks and on-site emergency power equipment. Alternative capacity requirements to the elevated storage requirements may be obtained based on request to and approval by the executive director. Special conditions apply to systems using an alternative capacity requirement to meet minimum pressure maintenance requirements.

      1. (A) The system must submit documentation sufficient to assure that the alternate method of pressure maintenance is capable of providing a safe and uninterrupted supply of water under pressure to the distribution system during all demand conditions.

         1. (i) A signed and sealed statement by a licensed professional engineer must be provided which certifies that the pressure maintenance facilities are sized, designed and capable of providing a minimum pressure of at least 35 psi at all points within the distribution network at flow rates of 1.5 gpm per connection or greater. In addition, the engineer must certify that the emergency power facilities are capable of providing the greater of the average daily demand or 0.35 gpm per connection while maintaining distribution pressures of at least 35 psi, and that emergency power facilities powering production and treatment facilities are capable of supplying at least 0.35 gpm per connection to storage.
         2. (ii) The system's licensed professional engineer must conduct a hydraulic analysis of the system under peak conditions. This must include an analysis of the time lag between the loss of the normal power supply and the commencement of emergency power as well as the minimum pressure that will be maintained within the distribution system during this time lag. In no case shall this minimum pressure within the distribution system be less than 20 psi. The results of this analysis must be submitted to the commission for review.
         3. (iii) For existing systems, the system's licensed professional engineer must provide continuous pressure chart recordings of distribution pressures maintained during past power failures, if available. The period reviewed shall not be less than three years.

      2. (B) Emergency power facilities must be maintained and provided with necessary appurtenances to assure immediate and dependable operation in case of normal power interruption.

         1. (i) The facilities must be serviced and maintained in accordance with level 2 maintenance requirements contained in the current NFPA 110 standards and the manufacturers recommendations.
         2. (ii) The switching gear must be capable of bringing the emergency power generating equipment on line during a power interruption such that the pressure in the distribution network does not fall below 20 psi at any time.
         3. (iii) The minimum on-site fuel storage capacity shall be determined by the fuel demand of the emergency power facilities and the frequency of fuel delivery. An amount of fuel equal to that required to operate the facilities under-load for a period of at least 8 hours must always be maintained on site.
         4. (iv) Residential rated mufflers or other means of effective noise suppression must be provided on each emergency power motor.
      3. (C) Battery powered or uninterrupted power supply pressure monitors and chart recorders which are configured to activate immediately upon loss of normal power must be provided for pressure maintenance facilities. These records must be kept for a minimum of three years and made available for review by the commission. Records must include chart recordings of all power interruptions including interruptions due to periodic emergency power "under-load" testing and maintenance.
      4. (D) An emergency response plan must be submitted detailing procedures to be followed and individuals to be contacted in the event of loss of normal power supply.
   3. (3) Any alternative capacity requirement granted under this subsection shall be subject to review at the time of each routine sanitary survey of the system. Failure to demonstrate satisfactory survey findings may result in revocation of the alternative capacity requirement. If permission to use an alternative capacity requirement is revoked, the public water system must meet the applicable minimum capacity requirements of this section.

Source Note:The provisions of this §290.45 adopted to be effective October 1, 1992, 17 TexReg 6455; amended to be effective November 3, 1995, 20 TexReg 8620; amended to be effective February 4, 1999, 24 TexReg 731; amended to be effective September 13, 2000, 25 TexReg 8880; amended to be effective May 16, 2002, 27 TexReg 4127.