[Code of Federal Regulations]
[Title 40, Volume 21]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR257.22]

[Page 378-379]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
                   CHAPTER I--ENVIRONMENTAL PROTECTION
                           AGENCY (CONTINUED)
 
PART 257--CRITERIA FOR CLASSIFICATION OF SOLID WASTE DISPOSAL FACILITIES AND PRACTICES--Table of Contents
 
 Subpart B--Disposal Standards for the Receipt of Conditionally Exempt 
 Small Quantity Generator (CESQG) Wastes at Non-Municipal Non-Hazardous 
                          Waste Disposal Units
 
Sec. 257.22  Ground-water monitoring systems.

    (a) A ground-water monitoring system must be installed that consists 
of a sufficient number of wells, installed at appropriate locations and 
depths, to yield ground-water samples from the uppermost aquifer (as 
defined in Sec. 257.5(b)) that:
    (1) Represent the quality of background ground water that has not 
been affected by leakage from a unit. A determination of background 
quality may include sampling of wells that are not hydraulically 
upgradient of the waste management area where:
    (i) Hydrogeologic conditions do not allow the owner or operator to 
determine what wells are hydraulically upgradient; or
    (ii) Sampling at other wells will provide an indication of 
background ground-water quality that is as representative or more 
representative than that provided by the upgradient wells; and
    (2) Represent the quality of ground water passing the relevant point 
of compliance specified by the Director of an approved State or at the 
waste management unit boundary in an unapproved State. The downgradient 
monitoring system must be installed at the relevant point of compliance 
specified by the Director of an approved State or at the waste 
management unit boundary in an unapproved State that ensures detection 
of ground-water contamination in the uppermost aquifer. The relevant 
point of compliance specified by the Director of an approved State shall 
be no more than 150 meters from the waste management unit boundary and 
shall be located on land owned by the owner of the facility. In 
determining the relevant point of compliance the State Director shall 
consider at least the following factors: the hydrogeologic 
characteristics of the unit and surrounding land, the volume and 
physical and chemical characteristics of the leachate, the quantity, 
quality and direction of flow of ground water, the proximity and 
withdrawal rate of the ground-water users, the availability of 
alternative drinking water supplies, the existing quality of the ground 
water, including other

[[Page 379]]

sources of contamination and their cumulative impacts on the ground 
water, and whether the ground water is currently used or reasonably 
expected to be used for drinking water, public health, safety, and 
welfare effects, and practicable capability of the owner or operator. 
When physical obstacles preclude installation of ground-water monitoring 
wells at the relevant point of compliance at existing units, the down-
gradient monitoring system may be installed at the closest practicable 
distance hydraulically down-gradient from the relevant point of 
compliance specified by the Director of an approved State that ensures 
detection of groundwater contamination in the uppermost aquifer.
    (b) The Director of an approved State may approve a multi-unit 
ground-water monitoring system instead of separate ground-water 
monitoring systems for each unit when the facility has several units, 
provided the multi-unit ground-water monitoring system meets the 
requirement of Sec. 257.22(a) and will be as protective of human health 
and the environment as individual monitoring systems for each unit, 
based on the following factors:
    (1) Number, spacing, and orientation of the units;
    (2) Hydrogeologic setting;
    (3) Site history;
    (4) Engineering design of the units; and
    (5) Type of waste accepted at the units.
    (c) Monitoring wells must be cased in a manner that maintains the 
integrity of the monitoring well bore hole. This casing must be screened 
or perforated and packed with gravel or sand, where necessary, to enable 
collection of ground-water samples. The annular space (i.e., the space 
between the bore hole and well casing) above the sampling depth must be 
sealed to prevent contamination of samples and the ground water.
    (1) The owner or operator must notify the State Director that the 
design, installation, development, and decommission of any monitoring 
wells, piezometers and other measurement, sampling, and analytical 
devices documentation has been placed in the operating record; and
    (2) The monitoring wells, piezometers, and other measurement, 
sampling, and analytical devices must be operated and maintained so that 
they perform to design specifications throughout the life of the 
monitoring program.
    (d) The number, spacing, and depths of monitoring systems shall be:
    (1) Determined based upon site-specific technical information that 
must include thorough characterization of:
    (i) Aquifer thickness, ground-water flow rate, ground-water flow 
direction including seasonal and temporal fluctuations in ground-water 
flow; and
    (ii) Saturated and unsaturated geologic units and fill materials 
overlying the uppermost aquifer, materials comprising the uppermost 
aquifer, and materials comprising the confining unit defining the lower 
boundary of the uppermost aquifer; including, but not limited to: 
thicknesses, stratigraphy, lithology, hydraulic conductivities, 
porosities and effective porosities.
    (2) Certified by a qualified ground-water scientist or approved by 
the Director of an approved State. Within 14 days of this certification, 
the owner or operator must notify the State Director that the 
certification has been placed in the operating record.