Water safety: Lead, copper and the plumbing engineer
Insights into the issue and understanding how proposed LCR revisions may impact your work.
On Nov. 13, 2019, National Primary Drinking Water Regulations: Proposed Lead and Copper Rule revisions were published in the Federal Register for public comment.
This proposed rule is the culmination of years of work by the Environmental Protection Agency and stakeholders in updating the existing Lead and Copper Rule (LCR). The LCR was originally promulgated in 1991 and has had several minor revisions, with the most recent short-term revisions to the LCR occurring in 2007. Guided by The Federal Action Plan to Reduce Childhood Lead Exposures and Associated Health Impacts (2018), the EPA and other federal departments have been tightening standards to reduce exposure to lead from sources such as paint, air, soil, dust and drinking water.
Blood lead levels in the U.S. have decreased over the past decade with increases in regulations regarding the use of lead in products such as gasoline, paints and solder, and plumbing materials. However, there is still data showing adverse health effects associated with low-level lead exposure.
Remaining sources of lead exposure include lead-based paint and soil contaminated by legacy sources, and drinking water. Drinking water exposures from public water supplies have, in some cases, been covered extensively by the media (i.e. Flint, Michigan), but there are many other water systems with lead and copper exceedances that are less publicized and likely systems that have unknown exceedances. The proposed LCR revisions represent the next step in regulation to further reduce exposure to lead from drinking water.
What the plumbing engineer needs to know
The purpose of this article is not to hash through the technical details around lead control in drinking water systems, but rather to provide the plumbing engineer with some basic insight into the issue and an understanding of how the proposed LCR revisions may impact their work. In drinking water systems, the issue of lead can be simplified into a couple of key concepts:
- Lead impacts health: Lead can be toxic and exposure to elevated levels of lead has documented acute and chronic health impacts, such as nervous system impairment and kidney damage, especially in children and pregnant women.
- Legacy infrastructure issue: The source of lead in drinking water is primarily from legacy infrastructure near drinking water consumers (i.e. building plumbing systems). This infrastructure includes lead found in water distribution mains and service lines, goose necks, solder and joining materials, fittings, brass fixtures and appurtenances, and galvanized pipe downstream from lead piping.
- Lead exposure can be controlled: Exposure to lead in drinking water is currently being controlled through three methods: 1. Removal of lead-based materials; 2. Formation of pipe scales to contain lead; and 3. Filtration of water to capture lead before consumption.
Summary of proposed LCR revisions: The purpose of this article is also not to explain in detail the proposed LCR revisions (available online for anyone to review), but to give the plumbing engineer a general idea of the proposed requirements for public water systems. The purpose of the pro-posed rule is to further protect public health through education and additional reduction of lead and copper levels in drinking water. Sections of the proposed rule address items such as lead tap sampling, corrosion control treatment, lead service line replacement, consumer awareness and public education. The proposed rule includes updates to thresholds for levels for lead in drinking water, through the addition of a trigger limit of 10 µg/L of lead in addition to the current 15 µg /L action limit for lead. The proposed rule establishes revised corrective actions for public water systems when lead exceedances occur. Public water systems will also be required to conduct lead testing and education in all schools and child-care facilities served by the system.
The impact on the plumbing engineer
As noted above, details of the proposed LCR revisions are most applicable to public water systems permitted by the EPA to treat and distribute drinking water. The plumbing engineer, however, needs to be aware of this (and other) drinking water regulations because the building water systems under their design may receive, store, treat and distribute drinking water. How then can the LCR have an impact on the building plumbing system?
Plumbing engineers may be called upon to render an opinion or design improvements to building water systems. These requests may come after notification of LCR exceedances or concern for lead in drinking water at the consumer’s tap. Public water systems will be developing system inventories identifying potential and confirmed lead service lines and generally testing drinking water for lead levels. Specific testing of lead levels at the taps in schools and daycare facilities also will be offered. These inventories, lead testing and associated education of the public will likely result in building owners wanting to address lead. Plumbing work may involve identification and replacement of lead service lines, galvanized piping or fixtures/appurtenances to remove lead containing materials from the building plumbing system.
Plumbing engineers also need to be aware that the design of new building water systems could create conditions resulting in the release of and exposure to lead. There are three general conditions where this could occur.
Building construction, especially renovation and retrofits, often results in physical disturbances to piping systems. These disturbances occur from pipe tie-ins and physical work around piping systems, and can disrupt existing pipe scale, releasing lead to downstream plumbing systems. Acknowledging this potential, designing the work to minimize piping disruptions and specifying commissioning to flush and/or test can help minimize risk to occupants upon occupancy.
Implementation of building level water treatment systems (i.e. softening, filtration, disinfection) can result in changes to water quality. While some of these changes may be planned, such as reducing hardness, removing minerals or killing microorganisms, these changes in water quality could also adversely impact water chemistry provided by the public water suppler. When water chemistry changes, it may lead to disturbance or dissolving of pipe scales in an existing plumbing system. These changes could lead to corrosion in the plumbing system or if lead is present, disturbing pipe scales could result in the release of lead into the drinking water.
When designing building level water treatment systems, the plumbing engineer should ask: 1. Is there a potential for lead-based materials in the plumbing system? 2. What corrosion control treatment strategy is being applied by the public water supplier? and 3. Will the proposed water treatment system adversely impact water quality in the building?
Selection of plumbing materials often is made to meet code requirements, satisfy design constraints and meet budget requirements. There are plumbing regulations in place to minimize the presence of lead in new materials used in potable water. However, when connecting to existing piping systems that contain lead, brass or galvanized components, the plumbing engineer should be aware that material selection could impact corrosion and lead release due to dissimilar metals, differing pipe hydraulics and galvanic corrosion.
The design of nonpotable water systems may also require some awareness of the public water supplier’s corrosion control program. The concern here is not lead exposure, but how the supplied water quality could impact nonpotable systems such as cooling towers, pools/spas, decorative water features, etc. where there is additional water treatment, heating systems, exposure of water basins to light and dissimilar metals.
The proposed LCR revision was advertised for public comment, which ended Feb. 12, and a hearing entitled “EPA’s Lead and Copper Proposal: Falling Short of Protecting Public Health” was held on Feb. 11 by a House committee. The public now awaits finalization of the rule, with the EPA targeting 2020 with implementation likely starting in 2023.
In the meantime, the current federal LCR remains in effect and some states (such as Ohio and Michigan) have adopted more stringent local regulations around lead and copper. The plumbing engineer plays an important role in protecting the health of building occupants by designing plumbing systems that minimize the potential for exposure to lead and copper, and by providing engineering assistance to building owners to meet federal or local regulatory requirements.