Ever since I was a teenage lifeguard, I’ve been taught that we need to test the chlorine and pH of the pool, to make sure the health department doesn’t shut us down. It wasn’t until I started my professional career and became a Certified Pool Operator (CPO) that I started to understand why these two parameters matter.

During my first CPO course, I learned about recreational water illnesses (RWIs) and how they can spread in pools. While pool operators don’t need to understand the intricate details of how these various organisms can spread in the water, they should understand that, if you have people in the water, then diseases can spread. As pool operators, we are taught to keep the chlorine above 1 part per million (ppm) and the pH between 7.2 and 7.8.

Science has shown that, if we maintain these parameters, then the common RWIs found in pool water will be deactivated in a reasonable amount of time. For e. coli, the inactivation time under normal pool conditions is less than 1 minute. However, some germs like giardia can last up to 45 minutes under normal pool conditions. For this reason, the Centers for Disease Control and Prevention (CDC) recommends increasing chlorine levels in the event of a “fecal incident” to inactivate these germs quicker, before letting people back in the water.

The basic premise is that, since we don’t know what might be in our water, we need to treat towards the worst-case scenario to be safe. This is mostly due to the availability of testing methods for pool operators. For the most part, people must send samples off to a laboratory to check for the presence of e.coli or other RWIs. This limits the number of times the test can be done, while also increasing time that passes before the issue is known.

While attending the World Aquatic Health Conference last year, I was introduced to new technologies that allow an operator to test for various bacteria on site. These kits can test for e. coli, pseudomonas aeruginosa, shigella, legionella, and several other bacteria. The potential for a pool operator is exciting: Instead of just testing for the chlorine levels that should inactivate various bacteria, now we can test for the presence of the actual bacteria before and after treatment to confirm effectiveness. (Full disclosure: I now sit on the board of directors for Genemis Laboratories of America, which produces this technology.)

Several years ago, I was helping a client work with the local health department, which claimed to find high levels of coliform in the pool water. The operator could only ensure that proper chlorine and pH levels were maintained. They even went above and beyond by super-chlorinating the pool any time a storm occurred, so as to treat any run-off that entered the pool. Despite this, the pool continued to fail health department tests. The challenge: The operator and health official were testing for different things with different methods. The operator was testing chlorine levels, while the health office was testing for bacteria. The operator had no way to validate the health official’s test. Eventually, the parties learned that the lab results were faulty, but only after many long stressful hours of maintenance from the operator.

The recent shutdown of facilitates and their current reopening has brought another risk that can be prevented with the use of bacteria testing. The CDC, along with other health organizations, has warned that stagnant water sitting in building water systems can pose a risk of legionella outbreak. All water sources should be flushed out and ideally tested before allowing the public to use them.

The recent creation of fast on-site testing for bacteria can provide pool operators and facility owners with an added layer of testing, beyond the standard chlorine and pH monitoring required by code.