Even though I no longer own, operate or manage pools myself, I have friends who do, and on occasion they ask me questions about design, construction, operation, maintenance, sanitation and safety in and around pools. You’ll find most of the information you need in the CDC’s Model Aquatic Health Code, your local municipality’s swimming pool and spa code, and your local swimming pool and supply store.
“But wait,” you say. “What’s the MAHC?”
The Model Aquatic Health Code (MAHC) is a voluntary guidance document based on science and best practices that can help local and state authorities and the aquatics sector (pool owners/operators) make swimming and other water activities healthier and safer. States and localities can use the MAHC to create or update existing pool codes to reduce risk for outbreaks, drowning, and pool-chemical injuries. The MAHC guidelines are all-inclusive and address the design, construction, operation, maintenance, policies, and management cutting edge needs of today’s public aquatic facilities.
The burning question on many people’s minds is whether or not swimming pools are even safe given the modern environment of infectious disease.
Well, I’m sorry to report that while you can do everything right and greatly reduce the likelihood of waterborne disease, you’ll never eliminate it. Swimming pools and hot tubs CAN and DO facilitate the transmission of coronaviruses — including the Wuhan Coronavirus (COVID-19 from SARS-CoV-2) — not to mention many other pathogens aka “infectious agents” aka “germs,” including viruses, bacteria, fungi, algae, prions, and parasites.
“Oh, but I keep the water at 1.0 ppm chlorine and 7.5 pH, so I’m good to go!”
If that’s all you’re maintaining, then no, probably not. If your particulate matter is high, your pool is full of kids and/or adults, you live in a hot climate or one with plenty of sunshine, if your alkalinity is off, if your circulation is poor, if your chlorination levels aren’t steady…
Yes, there are indeed a large number of things to consider when it comes to maintaining a healthy quality of water in your pool. And, yes, I’m qualified to speak on this issue.
I’m a licensed pool operator, certified by Fairfax County, Virginia. Although I’m non-current (well over my three-year maximum), I managed pools in two states over four years, including countless hours installing, cleaning and repairing pool bottoms, sides, tiles, coping, decks, furniture, pumps, filters (low and high-rate sand, diatomaceous earth), and sanitation systems (NaOCl, Ca(ClO)2, and ClO2). In addition, I’ve been trained on and was certified to train others on more than sixty additional specific elements of water disinfection, water chemistry, mechanical systems, health and safety, and operations. Finally, I was also a Red Cross-certified Water Safety Instructor for four years i.e. I trained lifeguards, pool operators, and aquatics managers how to do their jobs safely and effectively.
I’ve also myself been the victim of improperly-maintained hot tubs and pools on multiple occasions, once with legionella (bacterial, 10% mortality rate), once with rotavirus (viral, <1% mortality), once with something that made my foot swell up overnight like a football, and several times with colds and the flu after swimming laps in pools whose water quality was ought of whack.
The PRIMARY KEYS to mitigating the spread of pathogens:
- Twice-daily or continuously maintain proper water chemistry
- Continuously eliminate pathogen-hosting debris
- Require showering before entry
- Bar entry to anyone showing any sign of being ill
- Do not allow over-crowding
“Is all this really necessary?”
If you either own, manage, operate or even attend a pool, public or private, then, YES — IT IS NECESSARY, particularly in light of today’s deadly pathogenic environment.
In light of the health hazards posed by swimming pools, it is essential to constantly monitor water quality in swimming pools and to assess the effectiveness of treatment and disinfection processes and compliance with standards. Specifically, appropriate chemical and microbial evaluation of water quality should be carried out, especially when large numbers of bathers are expected to use the pools. Overcrowding should in any case be prevented. Since the behavior of swimmers may affect water quality, strict rules of behavior in the pool should be followed and enforced, including shower before entering the water, wash hands after using the toilet, take children to bathroom before swimming, and, importantly, avoid swimming while sick.
Source: Bonadonna, L., & La Rosa, G. (2019). A Review and Update on Waterborne Viral Diseases Associated with Swimming Pools. International journal of environmental research and public health, 16(2), 166. https://doi.org/10.3390/ijerph16020166. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6352248/
“So, what do I need to do?”
If you’re responsible for maintaining a pool, even if it’s in your own backyard, please take the time to thoroughly review The Model Aquatic Health Code (MAHC) published by the U.S. Centers for Disease Control and Prevention. It is absolutely packed with far more information than you could possibly imagine, but also contains all the information you do require to maintain a healthy aquatic environment.
As of this writing, here are the latest versions of the MAHC and its Annex:
Good luck, swim safe, be safe, and enjoy the summer!