62-555.315. Public Water System Wells - Security; Number; Capacity; Under the Direct Influence of Surface Water; Control of Copper Pipe Corrosion and Black Water; and Disinfection and Bacteriological Surveys and Evaluations

In addition to the rules set forth in Chapters 62-524 and 62-532, F.A.C., the requirements of this section apply to public water system wells.

(1) Well Security. Wellheads shall be enclosed by fences with lockable access gates, housed in lockable buildings or enclosures, or otherwise protected against tampering, vandalism, and sabotage.

(2) Number of Wells. A minimum of two wells shall be connected to each community water system that is using only ground water and that is serving, or is designed to serve, 350 or more persons or 150 or more service connections.

(3) Well Capacity. The total well capacity connected to a water system using only ground water shall equal at least the system’s design maximum-day water demand (including design fire-flow demand if fire protection is being provided). In addition, if the water system is a community system serving, or designed to serve, 350 or more persons or 150 or more service connections, the total well capacity with the largest producing well out of operation shall equal at least the design average daily water demand, and preferably the design maximum-day water demand, for the system. If a community water system interconnects with another community water system to meet the requirements in subsection (2) above regarding number of wells, the total well capacity for the combined systems shall equal at least the total design maximum-day water demand for the combined systems and, with the largest producing well out of operation for the combined systems, shall equal at least the design average daily water demand, and preferably the design maximum-day water demand, for the combined systems.

(4) Wells Under the Direct Influence of Surface Water. Ground water from some wells, especially shallow wells and radial horizontal collector wells, and ground water from springs or infiltration galleries may be under the direct influence of surface water. The Department shall determine whether ground water is under the direct influence of surface water by using the procedures described in subsection 62-550.517(2), F.A.C., and subparagraph 62-550.817(2)(a)1., F.A.C. Suppliers of water using ground water that is determined by the Department to be under the direct influence of surface water shall comply with applicable requirements under Rule 62-550.817, F.A.C.

(5) Control of Copper Pipe Corrosion and Black Water. Applicants for a construction permit to connect a new or altered well to a community water system, except those applicants who have submitted a complete application to the Department before August 28, 2003, shall include in the preliminary design report or design data accompanying their permit application the results of measurements for alkalinity, dissolved iron, dissolved oxygen, pH, total sulfide, and turbidity in a minimum of one sample of raw water from the new or altered well. These measurements may be performed by any authorized representative of the supplier of water or applicant; but field measurements for dissolved oxygen, pH, and turbidity shall be performed following the appropriate procedures in the Department of Environmental Protection Standard Operating Procedures for Field Activities, DEP-SOP-001/01, as incorporated into Rule 62-160.800, F.A.C., and all other measurements shall be performed using an appropriate method referenced in subsection 62-550.550(1), F.A.C., or in Standard Methods for the Examination of Water and Wastewater as adopted in Rule 62-555.335, F.A.C. If the result for total sulfide equals or exceeds 0.3 mg/L, the applicant shall do the following:

(a) Provide aeration or other appropriate treatment of the water from the new or altered well to remove total sulfide as necessary. Recommended types of aeration treatment for different water quality ranges are listed in the table below, which is incorporated herein as guidance and not as a requirement. Direct chlorination shall not be used to remove (i.e., oxidize) 0.3 mg/L or more of total sulfide unless the elemental sulfur formed during chlorination is removed.

 

POTENTIAL FOR IMPACTS WITHOUT TOTAL SULFIDE REMOVAL	WATER QUALITY RANGES	POTENTIAL WATER TREATMENT
Low	Total Sulfide < 0.3 mg/L Dissolved Iron < 0.1 mg/L1	Direct Chlorination2
Moderate	0.3 mg/L  Total Sulfide  0.6 mg/L @ pH 7.2 or 0.3 mg/L  Total Sulfide 0.6 mg/L @ pH > 7.2	Conventional Aeration3 (maximum removal efficiency40-50%) or Conventional Aeration with pH Adjustment4,5 (maximum removal efficiency 40-50%)
Significant	0.6 mg/L < Total Sulfide 3.0 mg/L @ pH 7.2 or 0.6 mg/L < Total Sulfide 3.0 mg/L @ pH > 7.2	Forced Draft Aeration3 (maximum removal efficiency 90%) or Forced Draft Aeration with pH Adjustment4,5 (maximum removal efficiency 90%)
Very Significant	Total Sulfide > 3.0 mg/L	Packed Tower Aeration with pH Adjustment4,5 (maximum removal efficiency > 90%)
1High iron content raises concern if chlorination alone is used and significant dissolved oxygen exists in the source water. Filtration may be required to remove particulate iron prior to water distribution.
2Direct chlorination of sulfide in water in the pH range normally found in potable sources produces elemental sulfur and increased turbidity. Finished-water turbidity should not be more than two nephelometric turbidity units greater than raw-water turbidity.
3Increased dissolved oxygen entrained during aeration may increase corrosivity.
4Reduction of alkalinity during pH adjustment and high dissolved oxygen entrained during aeration may increase corrosivity. Corrosion control treatment such as pH adjustment, alkalinity recovery, or use of inhibitors may be required.
5High alkalinity will make pH adjustment more costly, and use of other treatment may be in order. Treatment that preserves the natural alkalinity of the source water may enhance the stability of finished water.

 

(b) Provide in the preliminary design report or design data accompanying the applicant’s permit application a water quality and treatment evaluation affirmatively demonstrating that the secondary maximum contaminant levels for color and odor will not be exceeded in the water supplier’s drinking water distribution system or in water customers’ potable water systems.

(6) Disinfection of Wells and Bacteriological Surveys and Evaluations of Wells. Wells shall be disinfected to inactivate any microbiological contaminant that may have been introduced into the wells during construction, repair, or maintenance and to allow the true microbiological character of well water to be determined through a bacteriological survey.

(a) Before new or altered wells, wells out of operation for more than six months, wells in which new pumping equipment has been installed, and wells taken out of operation for maintenance that might have contaminated the well are placed into, or returned to, operation, they shall be disinfected in accordance with Sections 1. through 4. and Section 5.2 of American Water Works Association (AWWA) Standard C654 as incorporated into Rule 62-555.330, F.A.C. In Section 5.2 of the aforementioned AWWA standard, references to Section 5.1 shall be interpreted to mean paragraph 62-555.315(6)(b) or (c), F.A.C., as appropriate. This paragraph does not apply to, and disinfection is not required for, wells that officially have been determined to be under the direct influence of surface water per subsection 62-550.517(2), F.A.C., and subparagraph 62-550.817(2)(a)1., F.A.C., and that are pumping to treatment plants with filtration and disinfection facilities meeting all applicable requirements in Rule 62-550.817, F.A.C.

(b) Following disinfection of a new or altered well or a well that has been out of operation for more than six months, a bacteriological survey of the well shall be conducted as set forth in subparagraphs 1. through 3. below unless the well is already considered microbially contaminated or susceptible to microbial contamination per subparagraph 2. below or paragraph (f) below. The total residual chlorine measurements required under subparagraph 1. may be performed by any authorized representative of the supplier of water or person constructing or altering the well but shall be performed following the appropriate procedures in the Department of Environmental Protection Standard Operating Procedures for Field Activities, DEP-SOP-001/01 as incorporated into Rule 62-160.800, F.A.C. The total coliform or E. coli analyses required under subparagraph 1. shall be performed by a laboratory of the Department of Health (DOH) or a laboratory certified by the DOH to perform bacteriological analyses of drinking water and shall be performed using an appropriate method referenced in subsection 62-550.550(1), F.A.C.

1. A total of at least 20 samples – each taken on a separate but consecutive workday and taken at least six hours apart from the other samples – shall be collected after first pumping the well to waste to remove all residual chlorine and then pumping the well to waste at a rate approximately equal to that of the permanent well pump for at least 15 minutes before each sample is collected, and the samples shall be analyzed for the presence of total residual chlorine, total coliform, and E. coli. Upon a showing by the supplier of water, or a determination by the Department, that historical records or other circumstances warrant it, the Department shall allow the required number of samples or the sample collection interval to be modified. Under no circumstances shall the Department allow fewer than ten samples to be collected, and under no circumstances shall the Department allow more than two samples to be collected per day. If the Department allows collection of two samples per day, the samples shall be collected at least six hours apart, and the well shall be pumped to waste for at least 15 minutes before each sample is collected.

2. If any sample shows the presence of free or combined chlorine, the sample shall be considered invalid. If any sample shows the presence of E. coli, the well shall be considered microbially contaminated unless the Department invalidates the sample or the supplier of water determines and eliminates the source of the E. coli, in which case the well shall be redisinfected in accordance with paragraph (a) above and resampled in accordance with subparagraph 1. above. If more than ten percent of the total number of samples collected show the presence of total coliform or if either of the last two samples collected shows the presence of total coliform, the well shall be redisinfected as necessary in accordance with paragraph (a) above and resampled in accordance with subparagraph 1. above or shall be considered susceptible to microbial contamination. If a well is considered microbially contaminated or susceptible to microbial contamination, the supplier of water shall provide treatment that reliably achieves at least four-log inactivation or removal of viruses in accordance with paragraph 62-555.320(12)(b), F.A.C. Additionally, the supplier of water shall conduct physical characteristics monitoring in accordance with subsection 62-550.517(2), F.A.C., when notified in writing by the Department to do so.

3. Bacteriological test results shall be considered unacceptable if the tests were completed more than 60 days before the Department received the results.

(c) Following disinfection of a well in which new pumping equipment has been installed or a well taken out of operation for maintenance that might have contaminated the well, a bacteriological evaluation of the well shall be conducted as set forth in subparagraphs 1. through 3. below unless the well is already considered microbially contaminated or susceptible to microbial contamination per subparagraph 62-555.315(6)(b)2., F.A.C., or paragraph (f) below. The total residual chlorine measurements required under subparagraph 1. may be performed by any authorized representative of the supplier of water but shall be performed following the appropriate procedures in the Department of Environmental Protection Standard Operating Procedures for Field Activities, DEP-SOP-001/01 as incorporated into Rule 62-160.800, F.A.C. The total coliform analyses required under subparagraph 1. shall be performed by a laboratory of the Department of Health (DOH) or a laboratory certified by the DOH to perform bacteriological analyses of drinking water and shall be performed using an appropriate method referenced in subsection 62-550.550(1), F.A.C.

1. After pumping the well to waste for at least 15 minutes with zero chlorine residual, a total of at least two samples – each taken on a separate day and taken at least six hours apart from the other sample(s) – shall be collected, and the samples shall be analyzed for the presence of total residual chlorine and total coliform.

2. If any sample shows the presence of free or combined chlorine, the sample shall be considered invalid. If any sample shows the presence of total coliform, the well shall be redisinfected as necessary in accordance with paragraph (a) above and resampled in accordance with subparagraph 1. above until two consecutive samples show the absence of total coliform.

3. Bacteriological test results shall be considered unacceptable if the tests were completed more than 60 days before the Department received the results.

(d) Except as allowed under paragraph (e) below and except as allowed under any special construction permit condition established in accordance with paragraph 62-555.533(2)(f), F.A.C., no disinfected well shall be placed into, or returned to, operation until a bacteriological survey or evaluation has been completed if required by paragraph (b) or (c) above, results of the survey or evaluation have been submitted to the appropriate Department of Environmental Protection (DEP) District Office or Approved County Health Department (ACHD) if a survey or evaluation is required, and said DEP District Office or ACHD has approved the well for operation.

(e) When installing new well pumping equipment for which a public water system construction permit is not required per subsection 62-555.520(1), F.A.C., or when taking a well out of operation for maintenance that might contaminate the well, the well may be returned to operation without the Department’s approval after completion of disinfection and after satisfactory completion of a bacteriological evaluation if such an evaluation is required under paragraph (c) above. If a bacteriological evaluation is required, the results of the evaluation shall be submitted to the appropriate Department of Environmental Protection District Office or Approved County Health Department along with the next monthly operation report(s) required under paragraph 62-555.350(12)(b), F.A.C., or if no monthly operation report is required under paragraph 62-555.350(12)(b), F.A.C., within ten days after the end of the month during which the evaluation was completed.

(f) All public water systems using ground water not under the direct influence of surface water are required by subsections 62-550.518(2), (3) and (10), F.A.C., to periodically sample the raw ground water for microbiological contamination. In the event a raw water sample is positive for E. coli, the relevant well(s) shall be considered microbially contaminated unless the Department invalidates the sample or the supplier of water determines and eliminates the source of the E. coli, after which the supplier of water shall disinfect and bacteriologically survey the well(s) in accordance with paragraphs (a) and (b) above. If a raw water sample is positive for total coliform bacteria and if the relevant well(s) are not already considered microbially contaminated or susceptible to microbial contamination, the supplier of water shall disinfect and bacteriologically survey the well(s) in accordance with paragraphs (a) and (b) above when notified in writing by the Department to do so.

Specific Authority 373.309, 373.337, 403.861(9) FS. Law Implemented 373.309, 403.861(12), (17) FS. History–New 11-19-87, Formerly 17-22.615, Amended 1-18-89, 5-7-90, 1-1-93, Formerly 17-555.315, Amended 8-28-03.