Plumbing Connections and Their Impact on Indoor Air Quality

Jan 30, 2017

Environmental Enlightenment #231

This issue has been contributed by Olivia Jacobs, a Certified Environmental Manager (Nevada) since 1995 and President of Clearwater Group (510-307-9943), a consulting and contracting firm in northern California. Olivia has been working on waste and sewerage and has been an enthusiast about civil infrastructure since 1982 when she was awarded a Watson Fellowship to study biogas and waste use, internationally.

Recently, she teamed with EPA Region 9´s Alana Lee and University of Kentucky´s Dr. Kelly Pennell to sample sewer air in manholes and cleanouts for contaminants at a superfund site and presented that work at the 2016 AEHS and CalCUPA conferences. Her Masters in Health Care Administration informs her interest in communicating the hazard identified by mapping the contaminants in the environment to protect human health from those contaminants migrating into indoor air. Her contracting background informs an interest in engineering a solution.

A simple-language explanation of maintenance necessary to prevent degradation of inside air in schools can be found at This 19-page guidance document outlines how our nation keeps its children safe within a maintained environment.

In particular, one of the elements is preventing sewer air from entering the built environment, and specifically from entering the indoor air in bathrooms. The EPA guidance document recommends the installation of automatic primers to prevent the entry of sewer gases ambient inside the sewer pipes into the indoor air.

Controlling Pollutants and Sources_Indoor Air Quality Design Tools for Schools; EPA 2016

Communication of hazards between industries is critical when it comes to challenges to public health. While the writers of this indoor air pollution prevention guidance document understood the need to prevent sewer gas from entering inside air, simply on the merits of hygiene, it is unlikely that they appreciated the need to do this based on the hazard content of the sewer air.

In fact, the ordinary and historic discharge of chemicals, and specifically dry cleaning compounds, to the sewer system has been well documented.

Use of Environmental Forensics in Drycleaning Invesigations. Robert Morrison, PhD. DPRA Inc. Hawaii, HI. Presentation at the State Coalition for Remediation of Drycleaners 2009 Annual Meeting, San Antonio, TX Nov 17-19, 2009

The release of these chemicals has resulted in the past and still results in current time in the spread of these chemicals through the pipes and throughout the subsurface.

The traditional chemicals used in dry cleaning contain carcinogenic elements. Their physical characteristics enable them to infiltrate concrete slabs, and migrate to underlying soil and down to groundwater with ease. They are referred to as persistent compounds and the fact that they volatilize and persist in the environment means that the trail of their discharge remains through the sewer system and in the sewer air.

Ami Adini Enlightenment article.

The extent of the releases, since every single residential area had their own dry cleaning shop in certain areas of certain states during a certain time period, cannot be underestimated. The following map does not even include chemical discharge from industries other than the dry cleaning industry.

Study of Potential for Groundwater Contamination from Past Dry Cleaner Operations in Santa Clara County, Thomas K.G. Mohr, Figure 21. Ranked Dry Cleaners in the Santa Clara Groundwater Sub basin.

The US EPA ( informs us that there are approximately 36,000 active dry cleaning facilities in the United States. This number includes commercial, industrial and coin-operated facilities.

Where there are solvents in the pipes, there are generally solvents in the sewer air. Since the pipes are connected, in a system, this suggests that contaminants in sewer air are likely associated with contaminants entering structures in the building envelope which has failed traps.

Add to this equation the use of bathroom fans which put a negative pressure on the sewer air where there is an open (dry) p-trap. The bathroom fan will effectively draw the sewer air into and through the bathroom. Depending on the air volumes and sewer air contaminants, the contaminants may persist in the bathroom or be removed from the building envelope through the exhaust outlet of the structure.

Conclusion – The schools acknowledge that dry p-traps result in exposure to sewer air … The migration of contamination has been documented by environmental science community … The extent of the use and releases in urban communities is well documented … The education of plumbers, maintenance workers and the general public needs to follow promptly, with leak detection technology developed and implemented to prevent indoor air contamination by sewer air contaminants.

Sewer Air Contaminant Migration into and through Building Envelope. Jacobs, Jacobs and Pennell, 2016


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