The types of drinking water treatment units (DWTU) are extremely diverse. The product category covers things from the historic carbon block used to filter contaminants out of water, to water softeners, reverse osmosis systems, and even products that use air to first generate the water and then reduce contamination from it. From the perspective of a novice, testing and certification may be perceived as something that only requires a few tests that verify a product is taking out the contaminants that the label advertises it will. However, when taking a deep dive into drinking water standards, you discover that there is a world of testing that the average person would never assume is done on these products. In total, there are four main categories of testing reviewed prior to establishing compliance with a DWTU standard.
MATERIALS SAFETY
Some consider this testing to be the most important aspect of testing. There is merit to this thought because while a product may be designed to take the lead out of water, it is possible that the materials used to make the product leach other harmful contaminants into the water. In layman’s terms, water can cause chemicals to get into the product stream simply by flowing over a given material. The extraction test is conducted to ensure that there are no harmful chemicals, above the allowable levels, getting into drinking water through simple contact.
STRUCTURAL INTEGRITY
Interestingly, the requirements for structural integrity evolved many years ago as a result of insurance companies being displeased with having to pay claims on point-of-entry water treatment devices that flooded basements due to leakage issues. From these concerns, it became a requirement that water treatment devices connected to the plumbing be subjected to rigorous cycle and hydrostatic structural tests. These tests are designed to push the units beyond their maximum working pressures to ensure that the products will maintain their integrity over the course of their effective life, even in high pressure events or extended use.
DESIGN AND CONSTRUCTION
This section is the best kept secret of drinking water treatment standards, but no less important. There are several tests detailed within the standards that relate to the design and construction of DWTUs and how it will impact critical aspects of the product in an end user’s home or business. A couple examples of these very product specific tests include the air gap test for reverse osmosis (RO) systems and the active agent test for filtration devices that contain an active agent, such as silver. Some ROs are equipped with air gap faucets used to ensure that there is no backflow into the RO system. While this is a beneficial feature, an air gap test is performed to ensure that this feature is functioning properly on these types of systems. Silver is an agent that is added to products to assist in minimizing bacterial growth. While this sounds like a good idea, there is potential to slough off silver throughout the life of the product. Because it is not recommended to ingest unlimited amounts of silver, for those products manufactured with this type of active agent, a test is conducted to ensure that silver is not in the product water above allowable levels. While these are not the only two tests that fall under this category, they provide examples of how the construction of these products can deem additional testing to establish compliance.
PERFORMANCE
This category is seemingly the obvious one. Testing is done to make sure that the contaminants the product is certified for are reduced by the treatment technology in the system. While this is certainly one aspect of the performance testing, there are other tests conducted that fall under the system’s performance. For example, for point-of-entry type products, a pressure drop (PD) test is performed to ensure that the unit does not cause a PD higher than 15 psi at its rated service flow. For water softeners, the amount of chlorides sent to the drain is evaluated to ensure that the systems are not being overwhelmed with too many chlorides. Additionally, filtration standards have tests to ensure that these products not only flow at a minimum rate, but also a test to ensure that they do not flow at a rate in which the integrity of the contaminant reduction testing would be in jeopardy.
Establishing compliance to the DWTU standards is a complicated process. The tests described above provide a good high-level view of what is needed, but only touch the surface of what is required to certify a drinking water treatment unit. However, the details above should at least provide evidence to the rigor that these products undergo to be certified.
