2019-081 Greywater and Impact FeesDate: April 19, 2019 Report No. 2019-081
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT:
Graywater capture to offset impact fees
EXECUTIVE SUMMARY:
In response to questions submitted by City Council members, staff has completed a quantitative
assessment of whether installing systems for graywater capture for irrigation could justify a
reduction or offset to impact fees for new construction projects that employ those systems.
BACKGROUND:
Graywater is defined in the Texas Administrative Code as wastewater discharged from showers,
bathtubs, clothes-washing machines, and sinks not used for food preparation or disposal or for
the disposal of hazardous or toxic ingredients. Use of graywater is regulated under 30 Chapter
285 §285.80 and §285.81 and under Chapter 210 §210.83. Graywater systems are allowed
without permit for domestic use under 400 gallons per day.
Impact fees represent the cost of capital required to meet the additional demand for new
developments. Impact fees are calculated based on the cost of capital to meet peak demand and
are assessed based on the projected peak demand of each service connection. In order to justify a
reduction or offset to impact fees for new construction projects, a permanent reduction in peak
water or wastewater demand must be established.
DISCUSSION:
Under Texas Administrative Code, graywater may be used for irrigation purposes when
collected. However, it may not be “disposed of using a spray distribution system,” preventing
graywater use by typical home automatic irrigation systems. As such, most modern automatic
irrigations couldn’t distribute graywater or would require a retrofit to distribute graywater. Users
could also install parallel irrigation systems for the automatic distribution of graywater or opt for
a manual distribution method. Any option adds additional infrastructure to be installed and
maintained by the system’s owner, and usage patterns would create varying impacts on peak
demand.
As water and wastewater capital projects rely on asset life expectancies upwards of 50 years,
peak demand projections must be reliable long-term. After graywater system installation, peak
demand reductions would rely on the ongoing maintenance and consistent operation of the
system as well as consistent discharges into the graywater capture system. Due to the high levels
of variation in these factors, a long-term reduction in peak demand cannot be supported by
system installation alone.
If a developer would like to reduce their water or wastewater impact fees, they would do so by
supporting the need for a smaller service connection. Impact fees for residences are most
commonly assessed at the smallest available size: 5/8”x3/4” for water services and 4” for
Date: April 19, 2019 Report No. 2019-081
wastewater services. When assessed impact fees are already at minimum, no lesser impact fees
are available.
While graywater systems are unlikely to reduce impact fees for new developments, they may
result in decreased utility bills based on reduced volume. An average customer may be able to
divert 2,000 gallons per month into a graywater capture system. This would reduce their utility
bill by $190.80-$352.80 per year, depending on water block rates, and this amount could
increase significantly if the customer is able to capture the maximum allowable volume under
TAC rule. Ongoing savings of operating graywater systems is likely to significantly exceed any
potential impact fee savings over the lifetime of the system.
CONCLUSION:
Staff does not find the installation and operation of graywater systems to be an effective method
toward reduction of impact fees relating to new development, however these systems can reduce
a customer’s utility fees through a reduction in water consumption.
ATTACHMENT(S):
Texas Administrative Code 30_1_210_F_210_83.pdf
Texas Administrative Code 30_H_ 285_80.pdf
Texas Administrative Code 30_H_ 285_81.pdf
STAFF CONTACT:
Tyler Dawson
Water and Wastewater Field Service Technical Manager
(940) 379-8944
Tyler.Dawson@CityofDenton.com
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TITLE 30 ENVIRONMENTAL QUALITY
PART 1 TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
CHAPTER 210 USE OF RECLAIMED WATER
SUBCHAPTER F USE OF GRAYWATER SYSTEMS
RULE §210.83 Residential Use of Graywater and Alternative Onsite Water
(a) An authorization from the commission is not required for the residential use of graywater and alternative
onsite water from a graywater reuse system or a combined reuse system when the total combined average is less
than 400 gallons per day and the water is used in accordance with this subchapter. Unless directed by the
executive director, an authorization from the commission is not required for the residential use of graywater and
alternative onsite water from a graywater reuse system or a combined reuse system when the total combined
average is greater than or equal to 400 gallons per day and the water is used in accordance with this subchapter.
(b) The graywater and alternative onsite water must originate from a private residence.
(c) Water from a graywater reuse system or a combined reuse system may only be used at the private residence
for the following purposes:
(1) to minimize foundation movement and cracking;
(2) for gardening;
(3) for composting;
(4) for landscaping; or
(5) for toilet or urinal flushing.
(d) Graywater reuse systems and combined reuse systems are not authorized to overflow onto the ground under
any circumstance.
(1) Graywater reuse systems must be designed and constructed so that the storage tank required by subsection
(e) of this section overflows to an organized wastewater collection system or an on-site sewage facility (OSSF)
unless prohibited by Chapter 285, Subchapter H of this title (relating to Disposal of Graywater). The graywater
must enter the organized wastewater collection system or OSSF through either one air gap or two backflow
valves or backflow preventers.
(2) Combined reuse systems must be designed and constructed so that 100% of the graywater can be diverted
to an organized wastewater collection system or an OSSF, unless prohibited by Chapter 285, Subchapter H of
this title, prior to entering the storage tank required by subsection (e) of this section. Graywater must be
diverted to the organized wastewater collection system or OSSF during periods of non-use of the system or if
the storage tank required by subsection (e) of this section reaches 80% capacity. The graywater must enter the
organized wastewater collection system or the OSSF through either one air gap or two backflow valves or
backflow preventers.
(3) Combined reuse systems that store stormwater, rainwater, and/or foundation drain water must have an
automatic shutoff system to stop the inflow of stormwater, rainwater, and foundation drain water into the
combined reuse system. The automatic shutoff system must activate when the storage tank required by
subsection (e) of this section reaches 80% capacity.
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(e) Except as authorized by subsection (j) of this section, graywater reuse systems and combined reuse systems
must store the water in tanks and the tanks must:
(1) be clearly labeled as non-potable water;
(2) restrict access, especially to children;
(3) eliminate habitat for mosquitoes and other vectors;
(4) be able to be cleaned; and
(5) meet the structural requirements of §210.25(i) of this title (relating to Special Design Criteria for
Reclaimed Water Systems).
(f) Graywater reuse systems and combined reuse systems must use piping that meets the piping requirement of
§210.25 of this title.
(g) Water from a graywater reuse system or a combined reuse system shall not be applied using a spray
distribution system except in accordance with the following conditions.
(1) Water from the spray distribution system must meet the following limits: Escherichia coli (E. coli) must be
less than 14 most probable number (MPN) or colony-forming units (CFU) per 100 milliliters for 30-day
geometric mean and less than 240 MPN or CFU per 100 milliliters maximum single grab sample.
(2) Water from the spray distribution system must be applied at times when people and pets are not actively
using the distribution area.
(3) Water from the spray distribution system must not be applied during rainfall events, when the ground is
frozen, or within 24 hours after one-half inch or more of rain.
(4) Water from the spray distribution system must be applied at a rate to prevent ponding, puddling, or runoff.
(5) Water from the spray distribution system must not be sprayed or allowed to drift off property.
(6) The spray distribution system must not be connected to a potable or raw water irrigation system unless
suitable backflow prevention is provided to protect the potable or raw water system.
(7) The spray distribution system must be inspected and repaired as needed to prevent discharges to water in
the state or off property.
(h) The property owner is responsible for ensuring that the graywater reuse system or combined reuse system is
properly operated and maintained to achieve the following requirements. Monitoring and recordkeeping for E.
coli and total suspended solids is not required. Property owners may refer to the regulatory guidance document
that is required by the Texas Health and Safety Code, §341.039, for assistance in complying with these
requirements.
(1) Graywater and alternative onsite water shall be treated to remove debris such as lint, leaves, twigs, and
branches prior to entering the storage tank by use of a 50 mesh screen.
(2) Swimming pool backwash and drain water cannot be used within five days after adding chemicals for
shock or acid treatment.
(3) Water from a graywater reuse system or a combined reuse system that is used for toilet or urinal flushing
must meet the following requirements.
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(A) E. coli must be less than 14 MPN or CFU per 100 milliliters for 30-day geometric mean and less than
240 MPN or CFU per 100 milliliters maximum single grab sample.
(B) Total suspended solids must be less than 10.0 milligrams per liter for 30-day geometric mean and less
than 30.0 milligrams per liter maximum single grab sample.
(C) All exposed piping and piping carrying graywater and/or alternative onsite water within a building must
be either purple pipe or painted purple; all buried piping must be either manufactured in purple, painted purple,
taped with purple metallic tape, or bagged in purple; and all exposed piping must be stenciled in yellow with a
warning reading "NON-POTABLE WATER."
(i) Builders of private residences are encouraged to:
(1) install plumbing in new housing to collect graywater and alternative onsite water from all allowable
sources, taking into consideration end-use requirements and maintaining sufficient blackwater waste flow; and
(2) design and install a subsurface distribution system around the foundation of new housing to minimize
foundation movement or cracking.
(j) Property owners who have been disposing of wastewater from residential clothes-washing machines,
otherwise known as laundry graywater, directly onto the ground prior to January 6, 2005, may continue
disposing of laundry graywater under the following conditions.
(1) The disposal area must not create a nuisance or threaten human health.
(2) Surface ponding must not occur in the disposal area.
(3) The disposal area must support plant growth or be sodded with vegetative cover.
(4) The disposal area must have limited access and use by residents and pets.
(5) Laundry graywater that has been in contact with human or animal waste must not be disposed onto the
ground surface.
(6) Laundry graywater must not be disposed onto an area where the soil is wet.
(7) A lint trap must be affixed to the end of the discharge line.
(8) The system has not been altered after January 6, 2005, has not created a nuisance, and does not discharge
graywater from any source other than clothes-washing machines.
Source Note: The provisions of this §210.83 adopted to be effective January 6, 2005, 29 TexReg 12195;
amended to be effective December 29, 2016, 41 TexReg 10364
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TITLE 30 ENVIRONMENTAL QUALITY
PART 1 TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
CHAPTER 285 ON-SITE SEWAGE FACILITIES
SUBCHAPTER H DISPOSAL OF GRAYWATER
RULE §285.80 General Requirements
(a) For the purpose of this chapter, graywater is defined as wastewater from showers; bathtubs; handwashing
lavatories; sinks that are used for disposal of household or domestic products; sinks that are not used for food
preparation or disposal; and clothes-washing machines. Graywater does not include wastewater from the
washing of material, including diapers, soiled with human excreta or wastewater that has come in contact with
toilet waste.
(b) Construction of a graywater reuse system, including storage and disposal systems, must comply with this
chapter; Chapter 210, Subchapter F of this title (relating to Use of Graywater and Alternative Onsite Water);
and any more stringent requirements of the local permitting authority. For the purposes of this subchapter, a
graywater reuse system begins at the graywater stub-out of a single family dwelling.
(c) A graywater reuse system must not create a nuisance or damage the quality of surface water or groundwater.
If a graywater reuse system creates a nuisance, threatens human health, or damages the quality of surface water
or groundwater, the permitting authority may take action under §285.71 of this title (relating to Authorized
Agent Enforcement of OSSFs).
(d) A graywater reuse system shall comply with the requirements of this subchapter as they existed on the date
installation was completed. The previous version of this subchapter is continued in effect for this purpose. Any
alterations to an existing system must comply with this chapter; Chapter 210, Subchapter F of this title; and any
more stringent requirements of the local permitting authority.
(e) No reduction in the size of the on-site sewage facility (OSSF) will be allowed when using a graywater reuse
system unless the OSSF meets all of the conditions and requirements of §285.81 of this title (relating to
Requirements and Conditions for Potentially Reducing the Size of an OSSF Disposal System for a Single
Family Residence with a Graywater Reuse System or a Combined Reuse System).
(f) If the OSSF is not a reduced OSSF as described in §285.81 of this title, the graywater from either a
graywater reuse system or a combined reuse system authorized under Chapter 210, Subchapter F of this title
may, be connected to the OSSF to dispose of the graywater during periods when graywater is not being reused.
If the reuse system is a combined reuse system as defined under Chapter 210, Subchapter F of this title, the
flows from alternative onsite water sources must be diverted and shall not be allowed to enter the OSSF.
Alternative water reuse systems as defined in Chapter 210, Subchapter F of this title, shall not be connected to
the OSSF as OSSFs are not authorized nor designed to treat or dispose of flows from alternative onsite water
sources. The piping connecting the graywater to the OSSF shall meet the applicable requirements of Subchapter
D of this chapter (relating to Planning, Construction, and Installation Standards for OSSFs).
Source Note: The provisions of this §285.80 adopted to be effective February 5, 1997, 22 TexReg 1114;
amended to be effective June 13, 2001, 26 TexReg 4115; amended to be effective January 6, 2005, 29 TexReg
12204; amended to be effective December 29, 2016, 41 TexReg 10378
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TITLE 30 ENVIRONMENTAL QUALITY
PART 1 TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
CHAPTER 285 ON-SITE SEWAGE FACILITIES
SUBCHAPTER H DISPOSAL OF GRAYWATER
RULE §285.81 Requirements and Conditions for Potentially Reducing the Size of an OSSF Disposal
System for a Single Family Residence with a Graywater Reuse System or a Combined
Reuse System
(a) Graywater reuse systems and combined reuse systems are authorized in Chapter 210, Subchapter F of this
title (relating to Use of Graywater and Alternative Onsite Water) without a permit, without the submission of
planning materials, and without meeting the requirements and conditions of this section. However, a
homeowner requesting an on-site sewage facility (OSSF) disposal system smaller than required in §285.33 of
this title (relating to Criteria for Effluent Disposal Systems) must obtain a permit and meet the requirements and
conditions of this section. Additionally, the potential reduction of the OSSF disposal system in this section only
applies to single family residence with a graywater reuse or a combined reuse system. OSSF disposal systems
for non-single family residences with a graywater reuse or a combined reuse system shall not have an OSSF
disposal system reduction.
(b) Effluent disposal system sizing. If the graywater reuse system or combined reuse system serving the single
family residence is in compliance with Chapter 210, Subchapter F of this title, the effluent disposal system
required in §285.33 of this title may be reduced in accordance with Table I in Figure: 30 TAC §285.81(b) of
this section.
Attached Graphic
(c) Verification of plumbing entering the OSSF. A licensed master plumber shall evaluate and document, after
the plumbing is installed, which sewage sources will be entering the OSSF. The documentation must be
provided to the OSSF permitting authority.
(d) Increased wastewater strength. When graywater is removed from the total sewage stream, the remaining
sewage stream entering the OSSF will have a higher organic strength. The resulting increase in sewage strength
shall be determined in accordance with Table II in Figure: 30 TAC §285.81(d) of this section.
Attached Graphic
(e) If the effluent disposal system does not require secondary treatment, either a professional sanitarian or a
professional engineer shall demonstrate with effective treatment design and supporting calculations that the
proposed treatment system will reduce the effluent quality down to 140 milligrams per liter five-day
biochemical oxygen demand (mg/l BOD5 ) prior to entering the effluent disposal system.
(f) If the effluent disposal system requires secondary treatment, then a professional engineer shall demonstrate
with effective treatment design and supporting calculations that the effluent quality meets the levels outlined in
§285.32(e) of this title (relating to Criteria for Sewage Treatment Systems).
(g) If the effluent disposal system is reduced based on the presence of a graywater reuse system or a combined
reuse system, a reserve area equivalent to the reduced area shall be shown to be available for future
construction of a disposal field should the graywater reuse system or combined reuse system be abandoned at a
later date. The reserve area shall meet the setbacks required by §285.91(10) of this title (relating to Tables) and
shall not be used for any surface improvements.
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(h) Graywater or alternative onsite water, as defined in Chapter 210, Subchapter F of this title, shall not be
applied to the surface of a reduced effluent disposal system.
(i) The reduced effluent disposal system is not sized to accommodate graywater. Therefore, there shall not be
any physical connection between the graywater reuse system or the combined reuse system and any part of the
OSSF without authorization from the OSSF permitting authority.
(j) In addition to the requirements outlined in Chapter 210, Subchapter F of this title, a graywater reuse system
or a combined reuse system, used in association with a reduced effluent disposal system under this section,
must have a storage tank capable of storing a volume of three days of graywater. The storage is necessary to
prevent application of graywater during periods when the landscape is saturated.
(k) Before a license to operate is issued for a reduced effluent disposal system allowed under this section, an
affidavit shall be properly filed and recorded in the deed records of the county. The affidavit must include the
owner's full name, the legal description of the property, a statement that the permit for the OSSF is transferred
to the new owner upon transfer of the property, a statement that the effluent disposal system is reduced due to
the presence of a graywater reuse system or a combined reuse system, a statement that the specified reserve
area shall not contain surface improvements, and a statement that the graywater reuse system or combined reuse
system cannot be connected to the OSSF without obtaining a permit from the OSSF permitting authority.
(l) If the property owner of a graywater reuse system or a combined reuse system on a property served by a
reduced effluent disposal system is convicted under or found in violation of any statute related to graywater or
public health nuisance, and the system is not properly repaired in a timely manner, the OSSF permitting
authority may require the graywater to be connected to the OSSF. If the OSSF permitting authority requires the
graywater to be connected to the OSSF, the effluent disposal system must be expanded to accommodate all the
flow required in §285.91(3) of this title, and the expansion must be permitted by the OSSF permitting authority.
Source Note: The provisions of this §285.81 adopted to be effective June 13, 2001, 26 TexReg 4115; amended
to be effective January 6, 2005, 29 TexReg 12204; amended to be effective December 29, 2016, 41 TexReg
10378
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