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Model Aquatic Health Code (MAHC) Review

Many people have been asking:

What is the current status of the MAHC and what is the best web site address to hit to see the current status of the modules for comments?

Here’s a link to the CDC’s webpage so you can check the status on each module.

Here’s a list of what we know has happened so far

Disinfection Water Quality:        Second Post after public comment 1/24/14

Regulatory Module:                      Second Post after public comment 1/24/14

Facility and Design:                      Second Post after public comment 12/16/13

Risk Management                         Second Post after public comment 7/23/13

Facility Maintenance                    Second Post after public comment 7/2/13

Monitor and Testing                     Second Post after public comment 6/05/13

Contamination Burden                Second Post after public comment 6/05/13

Fecal Contamination                    Second Post after public comment 5/30/13

Operator Training                         Second Post after public comment 04/08/11

Preface                                             Second Post after public comment 11/10/11

Recirculation/Filter System        First Post 7/02/13  They have not posted public comment or reposted after update.

Ventilation                                      First Post 4/13/11  They have not posted public comment or reposted after update.


Don’t forget to get your comments in!

How Bad is Peeing in the Pool?

Ladies and gentlemen, we have an epidemic of aquatic proportions on our hands: one out of five people freely admit to peeing in our pools.  Even Michael Phelps and Ryan Lochte have gone on record stating they frequently pee in pools.  But it’s not their fault; in fact peeing in the pool is a physiologic response to being in the water.



The water’s increased pressure on your immerged body (as compared to air) increases your fluid volume in circulation. One (of many) mechanisms to remove excess fluid from circulation is a peptide called Brain Natriuretic Peptide, BNP, (actually released in the heart), that likely along with its counterpart Atrial NP causes the kidney to “filter” out more water reducing the circulating volume, thus producing more urine.  This is your body’s mechanism of reducing the amount of work the heart has to do in response to more fluid in circulation.


But is peeing as bad it’s made out to be, well Stuart Jones, senior biochemist at Sense About Science , a London-based association, doesn’t seem to think so.  “Peeing in a swimming pool [sic] has very little impact on the composition of the pool water itself.”  He continues that “Urine is essentially sterile so there isn´t actually anything to kill in the first place… [it’s] largely just salts (ammonia) and water with moderate amounts of protein and DNA breakdown products.”  The oxidizers (e.g. chlorine) prevent that urine expelled bacteria from prorogating in the pool water.  From a volumetric analysis, an average lap pool has almost a half million liters (130,000 gallons) of water and a single urination produces only 0.2 liters.  You’d need a LOT of urine to affect the pool chemistry.


From an industry perspective, organic loadings have always been a concern for chloramine development leading to over chemical laden pools.  As a preventative measure aquatic staff has told patrons urine changes the color of the water.  I hate to be the bearer of bad news, but there is no such chemical additive to the pool; it’s even Snopes verified.  But that hasn’t stopped comedians or pop culture from seizing hold.





So what’s the big deal with peeing in the pool?  Well from a sanitation concern there really isn’t one, but from a health and comfort concern peeing may be the number one problem.  So for all those swimmers out there who complain about red-eyes in the pool, first STOP COMPLAINING … YOU’RE THE PROBLEM!  Second, stop peeing in the pool and making it worse for everyone else.


Pool Plaster Spalling – Improper Installation or Poor Water Chemistry?

11_viewpointPool plaster is made up of cement, sand and water.  It is commonly troweled onto a concrete pool shell in 3 to 5 separate passes – the early passes to place the material and the later passes to create a smooth final finish.  After plaster is troweled, excess water will bleed to the surface.  Bleed water then evaporates from the surface.  There are two common mistakes made during troweling.  First, if troweling is completed when bleed water is present it will force water back into the plaster paste which causes excessively high water to cement ratio which weakens the finished surface.  Second if troweling is completed late after the surface is too dry a crust will form with a wet paste underneath.  This will create a weakened zone subsurface.  This typically happens on dry, hot days with low humidity and wind.  If this happens, the finished surface will look fine and even last awhile if the pool is full of water.  However, when the pool is emptied, a 16th to an 8th inch layer of plaster will flake off or spall in small areas or spots.  Pool plaster spalling is a rare occurrence but most often happens in areas that are challenging to apply plaster including step areas, main drains, and shallow areas.  Often, the first reaction to pool plaster failure is to blame the pool water chemistry however improper installation is typically the cause of pool plaster spalling.

Revised MAHC Modules Posted: Disinfection & Water Quality, Regulatory

Centers for Disease Control and Prevention (CDC) sent this bulletin on 1/24/2014

Model Aquatic Health Code

Thank you for your interest in the Model Aquatic Health Code (MAHC), a collaborative effort of public health, academia, and industry working to protect individuals, families, and communities from preventable waterborne diseases and injuries through evidence-based guidance. Read below for the latest information.


The Disinfection and Water Quality Module and the Regulatory Module have been revised and re-posted after the first public comment period. View the revised modules and the response to comments documents.


The first full version of the MAHC is coming soon, and we want your feedback! We plan to release the first full version of the MAHC—a combination of all revised modules and supplemental information—in spring 2014 for a 60-day public comment period.

Get a head start!

Because the MAHC will be a long document, we encourage you to get a head start and begin compiling your comments now on the modules that have been revised after the first public comment period so that you have plenty of time to submit your feedback. The content of these modules will not change substantially, but we will have to reorganize information that may be duplicated in multiple modules and resolve conflicts where duplicate items make different recommendations. We will announce when the full version is posted and we are accepting public comments for 60 days.

Each module has a short synopsis or abstract highlighting the most critical recommendations.

You can monitor the status of all modules on the MAHC website.