If you have ever visited the plumbing section of your local hardware or home improvement store, you've probably seen a wide array of labeling printed on the product itself or on the packaging. Some products display standard designations such as NSF, ASTM or AWWA, while others display codes such as PW, RFH or DWV – it's like alphabet soup and can be confusing if you aren't familiar with these markings.
Products that are intended for contact with drinking water are generally reviewed under NSF/ANSI Standard 61 – Drinking Water System Components. This American national standard limits the amount of impurities that a product can potentially introduce into drinking water. Consumer products covered by this standard include:
Depending upon the type of product, one of the following designations may be present either on the product or the product packaging:
Another marking that is commonly found on pipe and fittings would be NSF-DWV. The "DWV" is an acronym that stands for Drain, Waste and Vent applications. Products bearing this mark have been reviewed for either for disposal of water/wastewater or for venting applications. Products with this marking only should not be used for potable water applications.
Effective January 1, 2010, manufacturers who want to sell products in California or Vermont must demonstrate that their products do not contain more than 0.25 percent lead by weighted average. This will become a national requirement in 2014. The weighted average lead content of a product is determined by multiplying the lead content of each component that is in contact with water by the surface area of that component, then dividing this number by the entire water contact surface area of the product.
Other markings can also be found on plumbing system components. Some of the more common ones include: