/As an apartment manager, why do my wash closets, sinks, and/or washers have a sewer smell (rotten egg/sulfur smell)?

Our office has recorded these “sewer smell” issues being correlated to at least two common events.

The first event is can be associated with the replacement of a hot water heater. The sewer smell, which is reduced sulfur, is a by-product of bacteria that were present within the water heater before the water heater’s commissioning. The destruction of those bacteria can be achieved through conformance with the disinfection procedures outlined within the Uniform Plumbing Code’s Chapter 6.

The second event occurs from the by-product of bacteria in the p-trap. The p-trap develops a biofilm over time. That biofilm provides a food source and medium of growth for the bacteria. Unless the biofilm is removed, either chemically or mechanically, the reduced sulfur smell will exit up through the p-trap whenever the water in the p-trap is disturbed. This correlation typically leads the observer to assume the smell is coming from the water exiting a faucet rather than from the water collected in the p-trap.

Either of these events may be occurring in an apartment where a sewer (rotten egg/sulfur smell) is present. Due to the isolated nature of these events, management offices will not likely receive complaints from other tenants. This is because the isolated events arise from the activities in the water system or sewer system of the effected apartment. This would not be a complex wide issue or a water main issue.

If you are looking into the installation of a reverse osmosis system. you may have deduced by now, the reduced sulfur smell is an issue which can be fixed/remedied with basic maintenance practices. Using a reverse osmosis system will not fix the source of this issue; it will merely mask the issue and require a commitment to replacing reverse osmosis system filters. Additionally, reverse osmosis systems are resource intensive and require on average 10 gallons of water to produce 1 gallon of final reverse osmosis filtered water. Depending upon use, this may increase a water bill, further adding to the operational cost commitment.

Overall, our office recommends your management office addresses the two types of events we have outlined to remedy this issue: follow the Uniform Plumbing Codes Chapter 6 to disinfect the hot water heater and the hot water pipes that lead from the water heater; and, clean out the p-traps in the effected apartment. We hope you have found this information informative, and you are always welcome to contact us with any questions. We are also interested in determining if these solutions correct this reduced sulfur issue, and look forward to hearing from you about the final results.