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Lead and Copper Rule | Drinking Water Compliance Assistance

Drinking Water Compliance Assistance

Lead and Copper Rule

Revised On: May 22, 2024 -  7:00 p.m..

The Lead and Copper Rule (LCR) protects public health by minimizing lead and copper levels in drinking water, primarily by reducing water corrosivity. Lead and copper enter drinking water mainly from plumbing materials containing lead and copper. All community water systems (CWSs) and non-transient non-community water systems (NTNCWSs) are subject to LCR requirements.

What to Do If There's an Exceedance

Lead or Copper Action Level

Traces of lead and/or copper are common in public water systems, but the goal is to minimize the public health risk of these contaminants as much as possible. The EPA has established an action level, or concentration of lead and copper, that is based on a 90th percentile of all samples during a monitoring period. In other words, at least 90 percent of all samples should be below the action level concentration.

Operators of public water systems must calculate the 90th percentile and report it to ADEQ within the first 10 days after the end of each monitoring period (40 CFR 141.90(a)(iv)). While ADEQ does not calculate the 90th percentile for public water systems, an estimate of the calculation can be found on ADEQ's Safe Drinking Water Database. To locate the estimate, enter water system information, look under "Sample Results" and "PBCU Summaries," and search items labeled 90% under "Type" | View Database >

Calculation tools:

When testing by a public water system shows that an action level for lead (0.015 milligrams per liter) or copper (1.3 milligrams per liter)  is exceeded, a series of treatment techniques are triggered called "the Corrosion Control Treatment Steps" and public water systems must:

  • Conduct water quality parameter monitoring
  • Notify the public and provide educational materials
  • Provide a corrosion control treatment recommendation
  • Execute corrosion control studies if required
  • Install state-designated corrosion control treatment|

Corrosion Control Resources for Public Water Systems 

  • Corrosion Control Study Requirements | View >
  • Corrosion Control Treatment Matrix | View >

Recent Regulatory Changes

*Please note that some of the changes made in the LCRR may be reversed by the LCRI when it is finalized. To assist you in navigating these changes, we recommend consulting the EPA’s Proposed Lead and Copper Rule Improvements Rule Comparison Guide | View > 

Significant changes made by LCRR/LCRI

Lead Service Line Inventory – public water systems are required to submit an initial inventory of all service lines and the material of which they are made that meets the elements of 40 CFR 141.84(a) by Oct. 16, 2024. Please note that ADEQ has funded and engaged several contractors to assist almost 700 small water systems (<10,000 people) with this inventory. To learn more about this project | Email > 

Additional information about this requirement is included further down on this page.

Public Education of Service Line Inventory – Public water systems must notify customers that are served by a lead, galvanized requiring replacement or lead status unknown service line as identified in the initial inventory within 30 days of submitting the initial inventory to the state following 40 CFR 141.85(e). By July 1, 2025, and annually thereafter, public water systems must provide a copy of this service line inventory notification to the state and demonstrate that it completed its annual consumer notifications per 40 CFR 141.90(f)(4).

Public Notices Lead Action Level Exceedances – There are multiple additional notification requirements, such as informing customers when Starting October 16, 2024, public water systems will also have to notify customers within 24 hours of learning of a lead action level exceedance, following 40 CFR 141.202. Public water systems must provide a copy of this notice to the state and EPA within 24 hours of learning of a lead action level exceedance following 40 CFR 141.31(d)(2).


Lower Lead Action Level (proposed under LCRI) – the current action level that triggers more monitoring and installation of corrosion control treatment is 15 parts per billion (ppb). The LCRI is proposing to lower the action level to 10 ppb. This change may become effective 3 years after the LCRI is docketed in Federal law.


Tap Sampling (proposed under LCRI) – the current sampling requirement is to take 1 liter from a tap used for drinking after the water has been stagnant for at least 6 hours. The proposed requirement is to take a 1-liter sample from the first liter and a sample of the fifth liter of water when the tap is turned on to be sampled. The higher of the first- or fifth-liter values at lead service line sites may be expected to be used when calculating the system’s 90th percentile at sites with lead service lines.

Lead Pipe Replacement (proposed under LCRI) – all public water systems with lead and galvanized requiring replacement service lines as declared in their inventory may be subject to replacement of these service lines within 10 years from the date this requirement is docketed in Federal law. A plan for how the water system will replace these service lines may also be required to accompany the inventory.

Multiple Lead Action Levels (proposed under LCRI) – public water systems that have three or more lead action level exceedances (>10 ppb) within a 5-year time period may be required to make filters available to all of their customers.

Roles of EPA and ADEQ relating to LCRR and LCRI

While the Federal Government has adopted the LCRR requirements, and will adopt the LCRI requirements by late 2024, Arizona has not yet adopted these changes. This means that enforcement of these requirements currently rests solely with the EPA. 

ADEQ will be proposing changes to Arizona law to incorporate the final requirements as per the LCRR and LCRI in 2025, and when finalized will be the primary regulatory authority on these requirements for the relevant public water systems in Arizona at that time.

Until the changes to Arizona law are made, EPA and ADEQ will work together to both educate and take necessary actions to safeguard Arizona’s communities from the risk of lead exposure in public water systems. Reporting by public water systems of lead service line inventories and other required activities will be made to ADEQ, and ADEQ will then work with EPA on any necessary enforcement actions. 

Current Regulatory Text:

You may read the current Federal LCRR legislation that has compliance deadlines affecting PWSs beginning on October 16, 2024 (40 CFR 141.31(d)(2), 141.84(a), 141.85(e), 141.90(e), 141.90(f)(4) and 141.202(a)(10)) in the LCRR Regulation Supplement Insert | View >

Proposed Regulatory Text:

The proposed LCRI and additional supporting information is available to the public for review and to provide written comments to EPA through the public docket (Docket ID No. EPA-HQ-OW-2022-0801) | View > 

Written comments must be received on or before Feb. 5, 2024 | Submit Comments >

Lead Service Line Inventory Project 

The LCR revisions impact more than 900 public water systems (PWSs) regulated by ADEQ by adding new regulatory and compliance requirements. All community and non-transient non-community PWSs are required to create a lead service line inventory to identify the materials for every service line in their water service area by Oct. 16, 2024. Public water systems serving > 50,000 people will need to post the lead service lines on a publicly available website.

To comply with the rule change, public water system staff will need to submit and manage service line data using an online portal called 120Water. The portal is free to use for all public water systems, and training is being provided starting in February to help meet the Oct. 16 deadline. 

At least one representative from every impacted public water system (community and non-transient non-community) will need to:

  • Register and watch 120Water training recording (fill out the form to receive resources by email) | Register Today > 
  • Create a 120Water account
  • Submit your inventory via 120Water by Oct. 16, 2024

To assist, ADEQ has created an initiative under the Drinking Water Technical Assistance program. This initiative will provide support to small public water systems by hiring third-party consultant firms to help the water systems inventory their service lines and report the results to both ADEQ and EPA. 

Lead Service Line Inventory Resources

  • Lead Service Line Inventory FAQs | View >
  • ADEQ Lead Service Line Template | Download (Excel) > 
  • Register for the next Open Office Hour | First Wednesday each month, 2:30 – 3:30 p.m. | Register >
  • Lead Service Line Inventory Office Hours Archive | View >
  • EPA Service Line Inventory Guidance | View >

Other Useful Resources

Due to the complexity of these alterations, we strongly encourage your active engagement to keep up-to-date on the implementation of these changes in Arizona via the following ways:

  • Webinars/meetings: look for upcoming ADEQ events | View >
  • Emails: sign up for our emails | View >
  • ADEQ website

Does your PWS need assistance with the Lead Service Line Inventory? 

If so, register to attend the next virtual Lead Service Line Inventory Open Office hour | Register >
Virtual open office hours are held monthly, first Wednesday, 2:30 – 3:30 p.m.