United States

Environmental Protection

Agency

Office of Water

(4606)

EPA 816-F-01-003

June 2001

Radionuclides Rule:

A Quick Reference Guide

Overview of the Rule

Title Radionuclides Rule

66 FR 76708

December 7, 2000

Vol. 65, No. 236

Purpose Reducing the exposure to

radionuclides in drinking water

will reduce the risk of cancer.

This rule will also improve

public health protection by

reducing exposure to all

radionuclides.

General

Description

The rule retains the existing

MCLs for combined radium-226

and radium-228, gross alpha

particle radioactivity, and beta

particle and photon activity.

The rule regulates uranium for

the first time.

Utilities

Covered

Community water systems, all

size categories.

Public Health Benefits

Implementation of

the Radionuclides

Rule will result in . . .

Reduced uranium

exposure for 620,000

persons, protection from

toxic kidney effects of

uranium, and a reduced

risk of cancer.

Estimated impacts of

the Radionuclides

Rule include . . .

Annual compliance costs

of $81 million.

Only 795 systems will

have to install treatment.

Critical Deadlines & Requirements

For Drinking Water Systems

June 2000 - December 8, 2003 When allowed by the State, data collected between these

dates may be eligible for use as grandfathered data

(excluding beta particle and photon emitters).

December 8, 2003 Systems begin initial monitoring under State-specified

monitoring plan unless the State permits use of

grandfathered data.

December 31, 2007 All systems must complete initial monitoring.

For States

December 2000 - December 2003 States work with systems to establish monitoring

schedules.

December 8, 2000 States should begin to update vulnerability assessments

for beta photon and particle emitters and notify systems

of monitoring requirements.

Spring 2001 EPA meets and works with States to explain new rules

and requirements and to initiate adoption and

implementation activities.

December 8, 2002 State submits primacy revision application to EPA. (EPA

approves within 90 days.)

Regulated Contaminants

Regulated

Radionuclide MCL MCLG

Beta/photon emitters* 4 mrem/yr 0

Gross alpha particle 15 pCi/L 0

Combined radium226/228 5 pCi/L 0

Uranium 30 μg/L 0

*A total of 168 individual beta particle and

photon emitters may be used to calculate

compliance with the MCL.
Initial Monitoring Results

< Detection Limit

> 1/2 the MCL but < the

MCL

> MCL

> Detection Limit but £1/2 

the MCL

2008 2009 2010 2011 2012 2013 2014 2015 2016

First Compliance Cycle

KEY

One sampling event.

4 consecutive quarterly samples. Systems with MCL 

violations must continue to take quarterly samples until 

4 consecutive samples are at or below the MCL.

When allowed by the State, data collected between 

6/00 and 12/08/03 may be used as grandfathered data 

to satisfy the initial monitoring requirements.

06/00 12/08/03

Grandfathered Data 

Collected between 

Final Rule

12/07/00

Initial Monitoring Begins 

unless State Permits the 

Use of Grandfathered Data

2004 2005 2006 2007

Initial Compliance 

Monitoring

Initial Monitoring Completed

12/31/07

For additional information

on the Radionuclides Rule

Call the Safe Drinking Water

Hotline at 1-800-426-4791;

visit the EPA Web site at

www.epa.gov/safewater; or

contact your State drinking

water representative. EPA

will provide radionuclide

training over the next year.

Applicability of the Standardized Monitoring Framework to Radionuclides

(Excluding the Beta Particle and Photon Emitters)

Monitoring Requirements

Gross Alpha, Combined Radium-226/228, and

Uranium (1)

Beta Particle and Photon

Radioactivity (1)

Initial Monitoring

Four consecutive quarters of monitoring. No monitoring required for most CWSs.

Vulnerable CWSs (2) must sample for:

 • Gross beta: quarterly samples.

 • Tritium and Strontium-90: annual samples.

Reduced Monitoring

If the average of the initial monitoring results for

each contaminant is below the detection limit: One

sample every 9 years.

If the average of the initial monitoring results for

each contaminant is greater than or equal to the

detection limit, but less than or equal to one-half

the MCL: One sample every 6 years.

If the average of the initial monitoring results for

each contaminant is greater than one-half the MCL,

but less than or equal to the MCL: One sample

every 3 years.

If the running annual average of the gross

beta particle activity minus the naturally

occurring potassium-40 activity is less than or

equal to 50 pCi/L: One sample every 3 years.

Increased Monitoring

A system with an entry point result above the MCL

must return to quarterly sampling until 4

consecutive quarterly samples are below the MCL.

If gross beta particle activity minus the

naturally occurring potassium-40 activity

exceeds 50 pCi/L, the system must:

 • Speciate as required by the State.

 • Sample at the initial monitoring frequency.

(1) All samples must be collected at each entry point to the distribution system.

(2) The rule also contains requirements for CWSs using waters contaminated by effluents from nuclear facilities.

Grandfathering of Data

When allowed by the State, data collected between June, 2000 and December 8, 2003 may be used

to satisfy the initial monitoring requirements if samples have been collected from:

 • Each entry point to the distribution system (EPTDS).

 • The distribution system, provided the system has a single EPTDS.

 • The distribution system, provided the State makes a written justification explaining why the

 sample is representative of all EPTDS.