| (a) General provisions.
(1) The requirements contained in this section are
to be used in evaluating both the total capacities for public water
systems and the capacities at individual pump stations and pressure
planes which serve portions of the system that are hydraulically separated
from, or incapable of being served by, other pump stations or pressure
planes. The capacities specified in this section are minimum requirements
only and do not include emergency fire flow capacities for systems
required to meet requirements contained in §290.46(x) and (y)
of this title (relating to Minimum Acceptable Operating Practices
for Public Drinking Water Systems).
(2) The executive director will require additional
supply, storage, service pumping, and pressure maintenance facilities
if a normal operating pressure of 35 pounds per square inch (psi)
cannot be maintained throughout the system, or if the system's maximum
daily demand exceeds its total production and treatment capacity.
The executive director will also require additional capacities for
a system that is unable to maintain a minimum pressure of 20 psi during
firefighting, line flushing, other unusual conditions, and systems
that are required to provide fire flow as specified in §290.46(x)
and (y) of this title.
(3) The executive director may establish additional
capacity requirements for a public water system using the method of
calculation described in subsection (g)(2) of this section if there
are repeated customer complaints regarding inadequate pressure or
if the executive director receives a request for a capacity evaluation
from customers of the system.
(4) Throughout this section, total storage capacity
does not include pressure tank capacity.
(5) The executive director may exclude the capacity
of facilities that have been inoperative for the past 120 days and
will not be returned to an operative condition within the next 30
days when determining compliance with the requirements of this section.
(6) The capacity of the treatment facilities shall
not be less than the required raw water or groundwater production
rate or the anticipated maximum daily demand of the system. The production
capacity of a reverse osmosis or nanofiltration membrane system shall
be the quantity of permeate water after post-treatment that can be
delivered to the distribution system. The amount available for customer
use must consider:
(A) the quantity of feed water discharged to waste;
(B) the quantity of bypass water used for blending;
(C) the quantity of permeate water used for cleaning
and maintenance; and
(D) any other loss of raw water or groundwater available
for use due to other processes at the reverse osmosis or nanofiltration
facility.
(7) If a public water system that is an affected utility
fails to provide a minimum of 20 psi or a pressure approved by the
executive director, or 35 psi, as required by TWC §13.1394 and §13.1395
respectively, throughout the distribution system during emergency
operations as soon as it is safe and practicable following the occurrence
of a natural disaster, a revised emergency preparedness plan or justification
regarding pressure drop shall be submitted for review and approval
within 180 days of the date normal power is restored. Based on the
review of the revised emergency preparedness plan, the executive director
may require additional or alternative auxiliary emergency facilities.
(8) A public water system that is an affected utility
is required to review its emergency preparedness plan once every three
years. An affected utility shall submit a new or revised emergency
preparedness plan to the executive director for approval within 90
days after any of the following conditions occur:
(A) An affected utility chooses to implement a different
option or options other than those in the most recent approved emergency
preparedness plan;
(B) A previously non-affected utility meets the definition
of an affected utility;
(C) An affected utility makes a significant change
as described in §290.39(j) of this title that affects emergency
operations; or
(D) An affected utility makes changes to utility contact
or emergency communications information. For these changes, the affected
utility must submit only the updated applicable pages of the emergency
preparedness plan to the executive director.
(b) Community water systems.
(1) Groundwater supplies must meet the following requirements.
(A) If fewer than 50 connections without ground storage,
the system must meet the following requirements:
(i) a well capacity of 1.5 gallons per minute (gpm)
per connection; and
(ii) a pressure tank capacity of 50 gallons per connection.
(B) If fewer than 50 connections with ground storage,
the system must meet the following requirements:
(i) a well capacity of 0.6 gpm per connection;
(ii) a total storage capacity of 200 gallons per connection;
(iii) two or more service pumps having a total capacity
of 2.0 gpm per connection; and
(iv) a pressure tank capacity of 20 gallons per connection.
(C) For 50 to 250 connections, the system must meet
the following requirements:
(i) a well capacity of 0.6 gpm per connection;
(ii) a total storage capacity of 200 gallons per connection;
(iii) two or more pumps having a total capacity of
2.0 gpm per connection at each pump station or pressure plane. For
systems which provide an elevated storage capacity of 200 gallons
per connection, two service pumps with a minimum combined capacity
of 0.6 gpm per connection are required at each pump station or pressure
plane. If only wells and elevated storage are provided, service pumps
are not required; and
(iv) an elevated storage capacity of 100 gallons per
connection or a pressure tank capacity of 20 gallons per connection.
(D) For more than 250 connections, the system must
meet the following requirements:
(i) two or more wells having a total capacity of 0.6
gpm per connection. Where an interconnection is provided with another
acceptable water system capable of supplying at least 0.35 gpm for
each connection in the combined system under emergency conditions,
an additional well will not be required as long as the 0.6 gpm per
connection requirement is met for each system on an individual basis.
Each water system must still meet the storage and pressure maintenance
requirements on an individual basis unless the interconnection is
permanently open. In this case, the systems' capacities will be rated
as though a single system existed;
(ii) a total storage capacity of 200 gallons per connection;
(iii) two or more pumps that have a total capacity
of 2.0 gpm per connection or that have a total capacity of at least
1,000 gpm and the ability to meet peak hourly demands with the largest
pump out of service, whichever is less, at each pump station or pressure
plane. For systems which provide an elevated storage capacity of 200
gallons per connection, two service pumps with a minimum combined
capacity of 0.6 gpm per connection are required at each pump station
or pressure plane. If only wells and elevated storage are provided,
service pumps are not required;
(iv) an elevated storage capacity of 100 gallons per
connection or a pressure tank capacity of 20 gallons per connection.
If pressure tanks are used, a maximum capacity of 30,000 gallons is
sufficient for up to 2,500 connections. An elevated storage capacity
of 100 gallons per connection is required for systems with more than
2,500 connections. Alternate methods of pressure maintenance may be
proposed and will be approved if the criteria contained in subsection
(g)(5) of this section are met; and
(v) emergency power for systems which serve more than
250 connections and do not meet the elevated storage requirement.
Sufficient emergency power must be provided to deliver a minimum of
0.35 gpm per connection and meet minimum pressure requirements to
the distribution system in the event of the loss of normal power supply.
Alternately, an emergency interconnection can be provided with another
public water system that has emergency power and is able to supply
at least 0.35 gpm for each connection in the combined system. Emergency
power must be maintained as required by §290.46(m)(8) of this
title.
(E) Mobile home parks with a density of eight or more
units per acre and apartment complexes which supply fewer than 100
connections without ground storage must meet the following requirements:
(i) a well capacity of 1.0 gpm per connection; and
(ii) a pressure tank capacity of 50 gallons per connection
with a maximum of 2,500 gallons required.
(F) Mobile home parks and apartment complexes which
supply 100 connections or greater, or fewer than 100 connections and
utilize ground storage must meet the following requirements:
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