C.M.R. 10, 144, ch. 202, app 144-202-A
Current through 2024-51, December 18, 2024
These standards set forth the operational parameters required for the proper chemical treatment and maintenance of public pool and spa waters.
Chemical treatment alone will not produce sanitary pool and spa water. A filtration system in proper operational condition is also required to attain clear, and sanitary water.
Public Pools - NSPI-1, NSPI-4, NSPI-9
Public Spas - NSPI-2
| 1. Sanitizer Levels | ||||
| a. Free chlorine, ppm | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-4 NSPI-9 | 1.0 | 1.0-3.0 | 4.0 | Hot water/heavy use may require operation at or near maximum levels. Test kits are available for a variety of free chlorine ranges. Free chlorine test color (DPD) may be completely or partially bleached by chlorine levels greater than 5 ppm to give a false low reading. For appropriate test kit, consult pool professional or test kit manufacturer. Regular oxidation is recommended and remedial practices may be necessary. |
| NSPI-2 | 3.0 | 4.0-5.0 | 8.0 | Public Spas: During hours of operation, test the water hourly, record results, maintain the ideal range continually and shock treat at the end of the daily use period. |
| b. Combined Chlorine, ppm | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-4 NSPI-9 | 0 | 0 | 0.2 | High combined chlorine results in reduced sanitizer efficacy. Take remedial action to reduce combined chlorine. Other signs of combined chlorine: Sharp chlorine-like chlorinous odor and eye irritation (e.g., mucous membrane). |
| NSPI-2 | 0 | 0 | 0.5 | |
| c. Total Bromine, ppm | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-4 NSPI-9 NSPI-2 | 3.0 6.0 | 3.0-5.0 6.0-8.0 | 7.0 10.0 | Hot water/heavy use may require operation at or near maximum levels. Regular oxidation is recommended. During hours of operation, test the water reqularly, record results, and maintain the ideal range continually. NSPI-2: Test water before use. During extended use test water hourly. Shock treat after use. |
| 2. Chemical Values | ||||
| a. pH | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | 7.2 | 7.4-7.6 | 7.8 | Operating pH at the minimum level requires alkalinity and hardness to be operated at a higher level. At maximum pH, calcium hardness and total alkalinity may have to be adjusted downward to maintain proper water balance. (See "saturation index" in NSPI Glossary.) If pH is too high: Low chlorine efficacy Scale formation Cloudy water Eye discomfort If pH is too low: Rapid dissipation of sanitizer Plaster and concrete etching Eye discomfort Corrosion of metals Vinyl liner wrinkling |
| b. Total Alkalinity (Buffering) ppm as CaCO3 | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | 60 | 80-100 For calcium hypochlorite, lithium hypochlorite and sodium hypochlorite 100-120 For sodium dichlor, trichlor, chlorine gas and bromine compounds | 180 | If total alkalinity is too low: pH bounce Corrosive tendency . If total alkalinity is too high: Cloudy water Increased scaling potential pH tends to be too high These values are based on carbonate alkalinity |
| c. Total Dissolved Solids (TDS) | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | NA | NA | 1500 ppm greater than TDS at pool start-up* *Start-up TDS includes source water TDS and any other inorganic salt added at start-up. | An increase in TDS may indicate an accumulation of impurtities during the course of operation. Excessively high TDS may lead to hazy water and scale formation, corrosion of fixtures, and may inhibit sanitation. TDS can be reduced by partial draining and addition of fresh water. For spas: TDS should be periodically reduced by draining. (See Section K. Water Replacement Procedure) |
| d. Calcium hardness, ppm as CaCO3 | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-4 NSPI-9 | 150 | 200-400 | 1000 | Lower alkalinity and lower pH must be used with hardness over 500 ppm. |
| NSPI-2 | 100 | 150-205 | 800 | |
| e. Heavy Metals | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | NA | NA | If excessive heavy metals (such as copper, iron, and manganese) are present: Staining may occur Water may discolor Filter cycle may decrease and require more frequent backwashing May indicate pH to low, corrosion, etc. | |
| 3. Biological Values(Maintaining adequate sanitizer levels is critical to prevent growth of algae and bacteria) | ||||
| a. Visible Algae | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | None Visible | None Visible | None Visible | If algae growth is observed recommendations may include but are not limited to: Superchlorinate the pool or spa. Use an EPA-registered algicide according to label directions. Supplement with brushing and vacuuming. Some algicides may cause foaming. |
| b. Bacteria | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | None | None | None | If bacteria count exceeds 0 CFU/100 ml, superchlorinate and follow proper maintenance procedures. |
| 4. Stabilizer (when used) | ||||
| a. Cyanuric Acid, ppm | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | 10 | 30-50 | 150 | If stabilizer is too low: Chlorine residual is rapidly destroyed by sunlight. If stabilizer is too high: May reduce chlorine efficacy to algae. NOTE: Stabilized chlorine use is prohibited for indoor pools. Cyanuric acid does not stabilize bromine sanitizers. |
| 5. Oxidation (Regular oxidation is recommended for pools and spas with normal bather load as a preventative treatment) | ||||
| a. Chlorine Products | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-4 NSPI-9 | As needed | Weekly | Determined by bather load, weather conditions, etc. | Some high use pools may require oxidation several times per week. Regular oxidation is recommended to prevent the build-up of contaminants, maximize sanitizer efficiency, minimize combined chlorine and improve water clarity. |
| NSPI-2 | At the end of each day facility is used. | |||
| b. Potassium Monopersulfate | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-4 NSPI-9 | As needed | Weekly | Determined by bather load, weather conditions, etc. | Some high-use pools may require oxidation several times per week. Regular oxidation is recommended to prevent the build-up of contaminants, maximize sanitizer efficiency, minimize combined chlorine and improve water clarity. Potassium monopersulfate will measure as combined available chlorine in DPD test system. Refer to test kit manufacturer's directions. |
| NSPI-2 | At the end of each day facility is used. | |||
| c. Hydrogen Peroxide | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | Monthly | As needed | Determined by bather load, weather conditions, etc. | Hydrogen peroxide should not be used as an oxidizer for pools and spas sanitized by chlorine dioxide. |
| d. Chlorine Dioxide | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-4 | As needed | 3-4 weeks | Determined by occurrence of biofilms in skimmer or plumbing or by abrupt disappearance of hydrogen peroxide. | No comments |
| 6. Remedial Practices | ||||
| a. Superchlorination | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | Follow label directions. Use a registered chlorine sanitizer. Do not enter pool or spa until water meets the prescribed values in Section A. Some sysptoms that may indicate a need for superchlorination are: Cloudy water Slime formation Musty odors Difficulty in maintaining a sanitizer residual Algaae and/or high bacteria counts | |||
| b. Superchlorination to establish breakpoint, dosage in ppm | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | At least 10 times combined chlorine | High dosage may be required to satisfy chlorine demand. If combined chlorine persists, water replacement should be considered. | ||
| c. Shock Treatment | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | Some conditions that may indicate a need for shock treatment are: Cloudy water Difficulty in maintaining a sanitizer residual Periods of heavy bather use Adverse weather Non-chlorine shocks are not sanitizers. They are effective in oxidizing organic contaminants. If the purpose of shock treatment is to treat bacteria or visible algae, an EPA registered product for that use should be used; follow label directions. Spas should be shock treated on a daily basis when used. | |||
| d. Chlorine Dioxide | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| As needed | Determined by occurrence of biofilms in skimmer or plumbing or by abrupt disappearance of hydrogen peroxide. | Follow label directions. | ||
| e. Clarification/Flocculation | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | As needed | Follow manufacturer's directions. | ||
| f. Algicides | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | As needed | Use U.S. EPA-registered products. Follow manufacturer's directions. Use of some algicides may cause foaming. | ||
| g. Foam Control | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | As needed | Foam may harbor persistent microorganisms. If foaming is not adequately controlled, consider daily shock treatment, water replacement, or an appropriate anti-foam agent. Follow manufacturer's directions. | ||
| 7. Temperature | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | Personal preference Personal preference | For pools: 78°F-82°F For spas: Personal preference | Personal preference 104°F | If temperature is too low: Bather discomfort If temperature is too high: Excessive fuel requirement Increased evaporation Bather discomfort Increased scaling potential Increased use of sanitizers Overexposure to hot water may cause nausea, dizziness and fainting. |
| 8. Water Clarity | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 | The deepest part of the pool or spa and/or main drain must be visible and sharply defined. | If water is turbid: Sanitizer level may be low Filtration/circulation system may require maintenance Improper chemical balance (Appendix A(2)) Consult remedial practices (Appendix A(6)) | ||
| 9. Ozone | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-4 NSPI-9 Concentration in air above pool or spa water, ppm | 0.1 over 8-hour time weighted average. | Serves as oxidizer of water contaminants. Must be used with EPA-registered sanitizer. Indoor installations should have adequate ventilation. | ||
| 10. Oxidation Reduction Potential (ORP) | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-1 NSPI-2 NSPI-9 | 650 MV | When chlorine or bromine is used as the primary sanitizer, ORP is commonly used to control sanitizer feed. The use of ORP controllers does not eliminate or supercede the neeed for testing the sanitizer level with standard test kits. ORP reading may be affected by a number of factors including, but not limited to pH, probe condition, cyanuric acid, sanitizer type, and supplemental oxidizers. Follow manufacturer's recommendations. | ||
| 11. Water Replacement | ||||
| NSPI Standard | Minimum | Ideal | Maximum | Comments |
| NSPI-2 | Water in spas/hot tubs that have high bather use requires partial or complete replacement of water periodically. | Water in spas/hot tubs that have high bather use requires complete replacement of water per the replacement guidelines below. | Water replacement is necessary to dilute dissolved solids, to maintain water clarity, and to do necessary routine maintenance. | |
C.M.R. 10, 144, ch. 202, app 144-202-A