Chapter 4: Open water systems

4.1 General

• 4.1.1 This chapter deals with open water systems located inside or outside buildings, as part of the facility.
• 4.1.2 Open water systems include decorative water features such as fountains, waterfalls, and open pools that aerosolize water.
• 4.1.3 Decorative water features are often located in the foyers or in common areas of many buildings and can pose a risk for Legionella bacterial growth.
• 4.1.4 In decorative water features, water is often sprayed or cascades over media, resulting in aerosols contaminated with bacteria.

4.2 Design requirements

• 4.2.1 This section applies to new systems and to upgrades to existing systems.
• 4.2.2 Incorporate provision for maintenance at the design stage.
• 4.2.3 Locate drains or sumps at the lowest level of the reservoir, with no low points that are not served by drains or sumps.
• 4.2.4 Provide access to equipment for maintenance.
• 4.2.5 Avoid stagnant areas or areas that are difficult to clean; use circulating pumps to maintain water flow.
• 4.2.6 Do not locate decorative water features near kitchen exhausts, plants, truck bays, or other sources of contamination.
• 4.2.7 Avoid water stagnation near submerged lighting, to reduce the risk of Legionella growth due to warmer temperatures.
• 4.2.8 Airflows should be directed toward the water feature, to reduce the risk of exposure for people in the vicinity.

4.3 Operation and maintenance

• 4.3.1 Any open water system not in operation for three or more consecutive days must be drained and shall have all components cleaned, disinfected, and then refilled.
• 4.3.2 Inspect visually for signs of microbial activity, algae, or debris.; inspection frequency to be at least once a week.
• 4.3.3 Clean all equipment and component water features at least once a week to reduce build-up of dirt, debris, and organic matter that can serve as nutrients for Legionella bacteria.
• 4.3.4 Disinfect system when bacterial testing results exceed action limits.
• 4.3.5 For disinfection, use an effective biocide program for microbiological control, complying with all federal, provincial/territorial, or municipal requirements.

4.4 Minimum bacterial testing requirements

Water sampling locations

• 4.4.1 Water sampling locations for bacterial testing shall be in accordance with the facility Legionella Bacteria Control Management Program (LBCMP).
• 4.4.2 The facility LBCMP should consider, at a minimum, the following locations for water sampling:
  • 4.4.2.1 Water reservoirs
  • 4.4.2.2 Filter assemblies

Bacterial testing results

• 4.4.3 Record the bacterial testing results on the facility LBCMP testing form (LBCMP-4).
• 4.4.4 Report the bacterial testing results in accordance with the regional and national reporting protocols.

Minimum bacterial testing requirements and frequency (normal operation)

• 4.4.5 While the system is in normal operation, perform weekly dipslide tests to determine the total bacteria count (TBC) at each water sampling location. Refer to Figure 2: Open water system bacterial test protocol normal mode located in Appendix D.
• 4.4.6 While the system is in normal operation, every two months perform Legionella bacteria culture tests to identify total Legionella pneumophila including all serogroups (LPTOT) bacteria levels. Refer to Figure 2: Open water system bacterial test protocol normal mode located in Appendix D.
• 4.4.7 Perform a qPCR test 24 hours after completion of the system start-up cleaning and disinfection. Refer to Figure 2: Open water system bacterial test protocol normal mode located in Appendix D.

Minimum bacterial testing requirements (emergency mode)

• 4.4.8 Use the emergency-mode bacterial test procedure if:
  • 4.4.8.1 There have been multiple reported cases of Legionnaires' disease in the past 30 days in the region within a 10 km radius of the building location and/or,
  • 4.4.8.2 The building has had recurring Legionella bacteria levels detected by the Legionella bacteria culture test that required disinfection of the system within the past 90 days and/or,
  • 4.4.8.3 Regional Health authorities direct more stringent bacterial testing.
• 4.4.9 Unless directed otherwise by the regional health authority, or due to regional restrictions, a weekly Quantitative Polymerase Chain Reaction (qPCR) test should be performed to obtain rapid, Legionella specific results, to determine the Legionella Pneumophila bacteria count at each water sampling location.

Dipslide testing limits and actions

• 4.4.10 (Level D1—Green)—When the TBC is less than 10,000 cfu:
  • 4.4.10.1 Continue with normal O&M.
• 4.4.11 (Level D2—Yellow)— When TBC is greater than or equal to 10,000 and less than or equal to 100,000 cfu:
  • 4.4.11.1 Review and adjust the O&M procedures and the water treatment program as required to ensure acceptable bacterial levels in the system.
  • 4.4.11.2 Continue operation with adjusted O&M and water treatment program.
• 4.4.12 (Level D3—Orange)—When TBC exceeds 100,000 cfu/mL:
  • 4.4.12.1 Shut down the system within 7 days and perform cleaning and disinfection procedures in accordance with one of the following two options.
    • 4.4.12.1.1 Option 1—Shut down within 48 hours to perform cleaning and disinfection procedure.
    • 4.4.12.1.2 Option 2—Perform a running disinfection within 48 hours. Shut down within 7 days to perform cleaning and disinfection procedure.
  • 4.4.12.2 Review and adjust the O&M procedures and the water treatment program as required to ensure acceptable bacterial levels in the system.
  • 4.4.12.3 Continue operation with adjusted O&M and water treatment program.
  • 4.4.12.4 Wait 2 to 7 days then perform a Legionella bacteria culture test in accordance with clauses 4.4.13 through 4.4.17 below.

Legionella bacteria culture testing limits and actions

• 4.4.13 Perform Legionella bacteria culture test in accordance with ISO 11731-1998 and ISO/TS 11731-2-2004.
• 4.4.14 Where the analysis result indicates interfering flora are present that may have affected the results:
  • 4.4.14.1 Perform a running disinfection of the system within 48 hours.
  • 4.4.14.2 Review and adjust the O&M procedures and the water treatment program as required to ensure acceptable bacterial levels in the system.
  • 4.4.14.3 Wait 2 to 7 days then perform a Legionella bacteria culture test in accordance with clauses 4.4.13 through 4.4.17.
• 4.4.15 (Level C1—Green)—When the LPTOT count is less than 1 cfu/mL:
  • 4.4.15.1 Continue with normal O&M.
• 4.4.16 (Level C2—Orange)—When the LPTOT count is greater than or equal to 1 and less than or equal to 100 cfu/mL:
  • 4.4.16.1 Shut down the system within 7 days and perform cleaning and disinfection procedures in accordance with one of the following two options.
    • 4.4.16.1.1 Option 1—Shut down within 48 hours to perform cleaning and disinfection procedure.
    • 4.4.16.1.2 Option 2—Perform a running disinfection within 48 hours. Shut down within 7 days to perform cleaning and disinfection procedure.
  • 4.4.16.2 Review and adjust the O&M procedures and the water treatment program as required to ensure acceptable bacterial levels in the system.
  • 4.4.16.3 Continue operation with adjusted O&M and water treatment program.
  • 4.4.16.4 Wait 24 hours then perform a qPCR test in accordance with clauses 4.4.18 through 4.4.21.
• 4.4.17 (Level C3—Red)—When the LPTOT count exceeds 100 cfu/mL:
  • 4.4.17.1 Immediately implement measures that will eliminate water dispersion by aerosol from the system then clean and disinfect the system before putting it back into service.
  • 4.4.17.2 Review and adjust the O&M procedures and water treatment program to ensure acceptable bacterial levels in the system.
  • 4.4.17.3 Continue operation with adjusted O&M and water treatment program.
  • 4.4.17.4 Wait 24 hours then perform a qPCR test in accordance with clauses 4.4.18 through 4.4.21.

Quantitative polymerase chain reaction testing limits and actions

• 4.4.18 Perform qPCR Test in accordance with ISO/TS 12869.
• 4.4.19 (Level Q1—Green)—When the Legionella pneumophila bacteria count is less than 10 GE/mL:
  • 4.4.19.1 Continue with normal O&M.
  • 4.4.19.2 Wait 2 to 7 days then perform a Legionella bacteria culture test in accordance with clauses 4.4.13 through 4.4.17.
• 4.4.20 (Level Q2—Yellow)—When the Legionella pneumophila bacteria count is between 10 and 100 GE/mL:
  • 4.4.20.1 Review and adjust the O&M procedures and adjust the water treatment plan as required to ensure acceptable bacterial levels in the system.
  • 4.4.20.2 Continue operation with adjusted O&M and water treatment program.
  • 4.4.20.3 Wait 2 to 7 days then perform a Legionella bacteria culture test in accordance with clauses 4.4.13 through 4.4.17.
• 4.4.21 (Level Q3—Orange)—When the Legionella pneumophila bacteria count exceeds 100 GE/mL:
  • 4.4.21.1 Shut down the system within 7 days and perform cleaning and disinfection procedures in accordance with one of the following two options.
    • 4.4.21.1.1 Option 1—Shut down within 48 hours to perform cleaning and disinfection procedure.
    • 4.4.21.1.2 Option 2—Perform a running disinfection within 48 hours. Shut down within 7 days to perform cleaning and disinfection procedure.
  • 4.4.21.2 Review and adjust the O&M procedures and the water treatment program as required to ensure acceptable bacterial levels in the system.
  • 4.4.21.3 Continue operation with adjusted O&M and water treatment program.
  • 4.4.21.4 Wait 24 hours then perform a qPCR test in accordance with clauses 4.4.18 through 4.4.21.

4.5 Operation, maintenance and testing schedule

• 4.5.1 Table 4.1 below indicates a summary of the minimum frequency for operation, maintenance and testing requirements of open water systems.