Excerpt from:
Chapter 210 - Use of Reclaimed Water
SUBCHAPTER F: USE OF GRAYWATER SYSTEMS 210.81 - 210.85
Effective January 6, 2005 210.81. Applicability.
"Adopted December 15, 2004 Effective January 6, 2005 210.82.
General Requirements.
(a) Graywater is defined as wastewater from:
(1) showers;
(2) bathtubs;
(3) handwashing lavatories;
(4) sinks that are not used for disposal of hazardous or toxic ingredients;
(5) sinks not used for food preparation or disposal; and
(6) clothes-washing machines.
(b) Graywater does not include wastewater from the washing of material, including diapers, soiled with human excreta or wastewater that has come into contact with toilet waste.
(c) Construction of a graywater system, including storage and disposal systems, must comply with this chapter and any requirements of the local permitting authority."
Section A(4) pertains to what you are asking and is not considered to be grey water and must be disposed of as black water.
Ive considered running my laundry seperate but cannot find anything much about storage and disposal in TX other than it cannot create runoff, pool, or be dispersed under pressure (such as through a lawn sprinker)