The state of New Mexico does not require a permit for private residential greywater systems that follow the following guidelines.

This was copied from the state site on on 9/1/09. Download a brochure from NM Env. Department on the rule here. 

20.7.3.810 GRAYWATER DISCHARGES: Graywater discharge of less than 250 gallons per day of private residential graywater originating from a residence for the resident’s household flower gardening, composting or landscaping irrigation shall be allowed if:

A. a constructed graywater distribution system provides for overflow into the sewer system or on-site wastewater treatment and disposal system;

B. a graywater storage tank is covered to restrict access and to eliminate habitat for mosquitos or other vectors;

C. a graywater system is sited outside of a floodway;

D. graywater is vertically separated at least five feet above the ground water table;

E. graywater pressure piping is clearly identified as a nonpotable water conduit;

F. graywater is used on the site where it is generated and does not run off the property lines;

G. graywater is discharged in a manner that minimizes the potential for contact with people or domestic pets;

H. ponding is prohibited, discharge of graywater is managed to minimize standing water on the surface and to ensure that the hydraulic capacity of the soil is not exceeded;

I. graywater is not sprayed;

J. graywater is not discharged to a watercourse;

K. graywater use within municipalities or counties complies with all applicable municipal or county ordinances enacted pursuant to Chapter 3, Article 53 NMSA 1978;

L. graywater is not stored longer than 24 hours before being discharged;

M. graywater use for purposes other than irrigation or composting is prohibited, unless a permit for such use is issued by the department;

N. graywater is not used to irrigate food plants except for fruit and nut trees;

O. graywater is discharged to a mulched surface area or to an underground irrigation system;

P. graywater is not discharged closer than 100 feet to a watercourse or private domestic well, or closer than 200 feet to a public water supply well;

Q. graywater does not create a public nuisance;

R. for residential units using an on-site liquid waste system for blackwater treatment and disposal, the use of a graywater system does not change the design, capacity or absorption area requirements for the on-site liquid waste system at the residential unit, and the on-site liquid waste system is designed and sized to handle the combined blackwater and graywater flow if the graywater system fails or is not fully used; and

S. graywater does not contain hazardous chemicals derived from activities such as cleaning car parts, washing greasy or oily rags or disposing of waste solutions from home photo labs or similar hobbyist or home occupational activities.

[20.7.3.810 NMAC – Rp, 20.7.3.310 NMAC, 9/1/05]