Why We Need a Water Seal to Protect Health


As a result of a series of cholera outbreaks in London in the mid-1800s, doctors and public health officials learned that what was then termed as "malfunctioning plumbing" produced aerosols, which today we call sewer gasses.  Filled with harmful microorganisms, mostly from human feces, the result is often disease.

Those days in London, public showers, bathrooms, and even clothes washing areas were shared by most of the population.  The creation of sewer gasses, which drifted back up the sewer pipes in these public areas, were typically the result of plumbing that was not designed correctly, had leaks, or because the U-traps in the drains had dried up.  These facts were described in an article written by Kristina Blom of Sweden's Karolinska University Hospital.[1]

It is now believed that malfunctioning plumbing was the cause of the cholera outbreak in London in the mid-1800s.  In time this problem became a worldwide pandemic.  Cholera can spread by inhaling sewer gasses or having direct or indirect contact with people who have the disease.  It is now believed that between 1846 and 1860, more than 600 people died as a result of this outbreak.

According to Blom, studies at the time of the outbreak, as well as similar studies conducted today, "stress the importance of [having] a physical barrier by a water seal between the drainage systems and surroundings." 

She adds that the absence of such a physical barrier was the cause of the Severe Acute Respiratory Syndrome (SARS) outbreak in 2003 at Amoy Gardens, a large apartment and shopping complex in Hong Kong.  "Aerosols can enter the ventilation system and spread to all the other connected rooms, igniting a fearsome spread [of disease].  The outbreak at Amoy Gardens highlights the need for good maintenance practices and water safety programs."

While public health officials at the time were stymied as to how to address the original "malfunction plumbing" problem in London, when the SARS outbreak began, "several different cleaning methods were tried, including hypochlorite (salt acids), mechanical (pressure washing), and pressurized steam at a temperature of more than 350 degrees (F)," says Blom.  "However, none of these methods worked.  This highlights the need for physical barriers such as water seals for drains that prevent the exposure to microbes in the drains and a way to control the integrity of the barrier."


Today we can address this problem very easily.  What are known as "liquid primers" keep the U-trap filled.  They prevent evaporation of water in drains and maintain the seal that blocks sewer gasses from being released.  Further, these primers are very weather tolerant, having the ability to perform effectively under both freezing and very hot conditions. 

"Preventive actions such as this are urgent," Blom adds, "and must be taken to reduce infections, allowing us to focus on the fundamental need for safe sanitation systems."


For more information on plumbing safety and ways to prevent the escape of sewer gasses, contact a Waterless Co representative.

[1] "Drainage systems, an occluded source of sanitation-related outbreaks," by Kristina Blom

Arch Public Health. 2015; Published online 2015 Feb 26.