New Mexico Administrative Code
Title 20 - ENVIRONMENTAL PROTECTION
Chapter 7 - WASTEWATER AND WATER SUPPLY FACILITIES
Part 3 - LIQUID WASTE DISPOSAL AND TREATMENT
Section 20.7.3.201 - PROCEDURES; GENERAL REQUIREMENTS

Universal Citation: 20 NM Admin Code 20.7.3.201

Current through Register Vol. 35, No. 18, September 24, 2024

A. Every owner shall be responsible for the storing, treating and disposing of liquid waste generated on that property. Every owner shall be responsible for ensuring that the liquid waste system on that property and any excavation related to the liquid waste system do not pose a public safety hazard.

B. No person shall discharge untreated liquid waste except into a permitted and approved enclosed system, a permitted and approved liquid waste treatment unit or a public sewer system, except for the discharge of graywater pursuant to 20.7.3.810 NMAC. All liquid waste systems installed in accordance with a liquid waste permit issued by the department prior to July 1, 2012 shall be deemed to have operational approval. No person shall discharge liquid waste or effluent into a cesspool or effluent disposal well.

C. No person shall discharge effluent from a liquid waste treatment unit except through a permitted and approved liquid waste disposal system or to a permitted public sewer system. No person shall discharge effluent from a liquid waste treatment unit to a cesspool or effluent disposal well.

D. No person shall install, have installed, modify or have modified, own, operate or use an on-site liquid waste system that, by itself or in combination with other on-site liquid waste systems, may cause a hazard to public health or degrade any body of water. All on-site liquid waste systems shall be installed, operated and maintained in accordance with the permit and applicable regulations.

E. All residential and commercial units utilizing an on-site liquid waste system shall connect to a public sewer upon availability and if required in accordance with the local authority that has jurisdiction. A public sewer shall be deemed available when the public sewer has capacity and is located in any thoroughfare, right-of-way or easement abutting the lot on which the residential or commercial unit is located. The on-site liquid waste system shall be properly abandoned in accordance with 20.7.3.307 NMAC within 30 days of connection to the public sewer.

F. The type of on-site liquid waste system shall be determined on the basis of location, lot size, soil and site characteristics. The system, except as otherwise approved, shall consist of a liquid waste treatment unit and associated disposal system.

G. An on-site liquid waste system shall be located wholly on the same lot, which is the site of the source or sources served by the on-site liquid waste system.

H. A privy may be used for the disposal of human excreta and toilet paper, but not for the disposal of other liquid wastes.

I. On-site liquid waste systems, other than holding tanks, receiving waste from recreational vehicles (RVs) shall provide treatment of the waste to concentrations equal to or less than primary treatment standards as defined in Paragraph (7), Subsection P of 20.7.3.7 NMAC, if necessary, prior to discharging to a conventional disposal system. Monitoring of the effluent may be required in accordance with 20.7.3.901 NMAC. Existing permitted on-site liquid waste systems receiving waste from recreational vehicles (RVs) shall continue to be authorized to operate. Upon modification of these existing systems, the system shall be required to provide the level of treatment of the waste identified above. This subsection shall not apply to homeowners who occasionally empty waste from one personal RV into the on-site liquid waste system serving their residence, provided that the RV is not used as a permanent living quarters.

J. On-site liquid waste systems permitted, but not installed, prior to the effective date of 20.7.3 NMAC shall be installed in accordance with the regulations in effect at the time of the permit issuance, provided that the installation of the system shall be completed within one year of the effective date of 20.7.3 NMAC.

K. Existing on-site liquid waste systems shall meet the regulations in effect at the time of their initial installation or subsequent modification or the current regulation, whichever is less stringent, unless otherwise noted in this regulation.

L. Nothing contained in 20.7.3 NMAC shall be construed to prevent the department from requiring compliance with more stringent requirements than those contained herein, where the department finds that such more stringent requirements are necessary to prevent a hazard to public health or the degradation of a body of water. The following parameters may be considered when determining if a body of water is potentially vulnerable to degradation from liquid waste effluents, and if more stringent requirements may be necessary to prevent such degradation:

(1) a water-table aquifer (includes both unconfined and semi-confined conditions) with a vadose zone thickness of 100 feet or less containing no soil or rock formation that would act as a barrier to saturated or unsaturated wastewater flow;

(2) sites within 1/4 mile of a known groundwater plume of anthropogenic anoxic or nitrate contamination caused by migration through undisturbed vadose zone, provided that the site overlies the same aquifer;

(3) an aquifer overlain by fractured bedrock;

(4) an aquifer in karst terrain; and

(5) a gaining stream or other body of water adversely affected by nutrients from liquid waste systems.

M. Upon written request, the department shall provide a letter of determination stating whether or not more stringent requirements may be imposed on a lot or parcel of land. This determination shall be valid for one year. The department shall issue the determination letter within 10 working days of receipt of the written request. This letter of determination in no way neither waives or precludes an applicant's regulatory requirements under this part nor predetermines the regulatory requirements of this part when obtaining a permit.

N. The secretary, or a designated representative, upon presentation of proper credentials and with consent or with an administrative search warrant:

(1) shall have the right of entry to any property on which a permitted or unpermitted on-site liquid waste system regulated by 20.7.3 NMAC exists or is required for the limited purpose of inspecting the liquid waste system or to determine compliance with these regulations or permit conditions; failure to provide reasonable access for the purpose of inspecting a liquid waste system or to determine compliance with these regulations or permit conditions shall be cause for revocation or suspension of a permit;

(2) shall have access to and may copy any record required to be established and maintained by these regulations or permit conditions; failure to provide reasonable access to or copies of any record required to be established and maintained by these regulations or permit conditions shall be cause for revocation or suspension of a permit; and

(3) may obtain any samples required to determine compliance with 20.7.3 NMAC or permit conditions; failure to provide reasonable access to facilities for the purpose of obtaining samples shall be cause for revocation or suspension of a permit.

O. Eligibility for permitting under 20.7.3.2 NMAC, which restricts effluent flow to 5,000 gallons per day or less, shall be determined as follows:

(1) Wastewater flows from residential sources shall be calculated at 80% of the design flow as determined according to Subsection P of 20.7.3.201 NMAC. Multiple families dwelling unit wastewater flows shall be calculated as the sum of wastewater flows for each single family unit included.

(2) Wastewater flows from residential and nonresidential sources shall be based on Table 201.1 or generally accepted references, such as the New Mexico plumbing code or the EPA design manuals for on-site wastewater treatment and disposal.

(3) Wastewater flows for residential and nonresidential sources also may be based on:
(a) professional engineering design calculations that bear the seal and signature of a professional engineer licensed in New Mexico, pursuant to the New Mexico engineering and surveying practice act and the rules promulgated under that authority; such calculations shall be reviewed by a department engineer, as appropriate; or

(b) the submittal of actual metered water use or effluent flow meter data; to use actual meter data to establish wastewater flow, the applicant must present at least one year of existing meter data collected within the previous five years; calculate the daily wastewater flow according to the following formula: A ÷ B = Q, where A = highest quarterly totalized meter reading in gallons for the minimum one year period; B = total number of days in highest metered quarter; Q = daily wastewater flow in gallons per day.

(c) Meter data or certification by a professional engineer shall not be used to determine wastewater flow on exclusively residential properties consisting of less than five residential units.

(d) If meter data is not representative of the actual wastewater discharge, as determined by the department, the applicant may be required to submit additional meter data or the department may disallow the use of meter data where its use would result in a gross misrepresentation of the wastewater discharge.

(e) The department may require a calibration of the meter used for determining water or wastewater flow and may disallow the use of inaccurate meter data. Applicants may be required to make future records of metered flow available for inspection by the department.

(f) If a permit is issued and there are meter records for any quarter that indicate the daily wastewater flow exceeds 5,000 gallons per day, quarterly meter records for the following two quarters shall be submitted to the department within 30 days of becoming available to the permittee. If meter data or other information available to department indicates the average daily wastewater flow has exceeded 5,000 gallons per day, the department may void the permit and refer the facility to the ground water quality bureau. The department may require a tamper-proof type meter be installed to verify that future wastewater flows do not exceed 5,000 gallons per day.

P. Determining treatment and disposal system design flow:

(1) For residential sources, the design flow shall be based on the number of bedrooms as follows:
(a) 1 bedroom = 150 gallons per day;

(b) 2 bedrooms = 300 gallons per day;

(c) 3 bedrooms = 375 gallons per day;

(d) 4 bedrooms = 440 gallons per day;

(e) 5 bedrooms = 500 gallons per day; and

(f) each additional bedroom = 50 gallons per day;

(g) design flows for multiple family dwelling units shall be calculated as the sum of design flows for each single family unit included.

(2) Where nonresidential wastewater flow is calculated based upon Table 201.1 or generally accepted references, no design factor is necessary to determine the design flow except as noted in Paragraph (3) below.

(3) For residential and nonresidential facilities with highly variable flows not certified by a professional engineer, a design factor greater than 1.5 may be required to be applied to determine the design flow. Alternatively, flow equalization or other methods of accommodating peak flows may be used with department approval.

(4) Where residential and nonresidential wastewater flow is certified by a professional engineer, no design factor is necessary to determine the design flow, unless deemed appropriate by the professional engineer.

(5) Where residential or nonresidential wastewater flow is determined using existing meter data and calculated in accordance with Subparagraph (b) of Paragraph (3) of Subsection O of 20.7.3.201 NMAC, a design factor of 1.5 shall be applied to the daily average flow to determine design flow. An additional peaking factor may be required in accordance with Paragraph (3) above.

(6) If the design flow could increase significantly beyond existing meter data due to increased occupancy or facility size, the department may require that additional area be available for future expansion of both the treatment and disposal systems.

Table 201.1: Established liquid waste design flow rates

TYPE OF OCCUPANCY GALLONS PER DAY
1. Airport, Bus Terminal, Train Station 20 per employee 5 per passenger
2. Beauty & Barber Shop 75 per service chair
3. Bowling alleys (snack bar only) 75 per lane
4. Bed and Breakfast 150 first bedroom 100 each additional bedroom
5. Camps: campground with central comfort station with flush toilets, no showers day camps (no meals served) summer and seasonal 35 per person 25 per person 15 per person 50 per person
6. Churches (Sanctuary) with kitchen waste 2 per seat 7 per seat
7. Dance hall 5 per person
8. Doctor and Dentist Office 250 per practitioner, 15 per employee
9. Factories, excluding industrial waste: per 8-hour shift no showers with showers cafeteria, add 25 per employee 35 per employee 5 per employee
10. Food Operations: Restaurants operating 16 hours or less per day Restaurants operating more than 16 hours per day Bar, cocktail lounge add per pool table or video game Carry out only, including caterers add per 8-hour shift Food outlets only add for deli add for bakery add for meat department add per public restroom 40 per seat 60 per seat 20 per seat 15 each 50 per 100 sq ft floor space 20 per employee 10 per 100 sq ft floor space 40 per 100 sq ft floor space 40 per 100 sq ft floor space 75 per 100 sq ft floor space 200
11. Hotels, Motels, Lodges laundries, lounges and restaurants calculated separately 60 per bed
12. Institutions (resident) nursing homes rest homes 75 per person 125 per person 125 per person
13. Laundries self-service (minimum 10 hours/day) commercial 50 per wash cycle per manufacturer's specifications
14. Offices 20 per employee per 8-hour shift
15. Parks: picnic park - toilets only 20 per parking space
16. Recreation Vehicles (RV) Park without water hookup with water and sewer hookup RV dump stations 75 per space 100 per space 50 per RV
17. Schools - staff and office elementary and day care intermediate and high boarding, total waste gym and showers, add with cafeteria, add 20 per person 15 per student 20 per student 100 per person 5 per student 3 per student
18. Service stations and convenience stores uni-sex restrooms 400 per toilet 800 per toilet
19. Stores public restrooms 20 per employee 10 per 100 sq ft. floor
20. Swimming and bathing places, including spas and hot tubs, public 10 per person
21. Theaters, auditoriums Drive-ins 5 per seat 10 per space
22. Veterinary Clinic add add 250 per practitioner 15 per employee 20 per kennel, stall, or cage

Liquid waste generated by the occupancies above, that exceeds the concentrations in the definition of domestic liquid waste, shall require treatment to primary treatment standards as defined in Paragraph (7), Subsection P of 20.7.3.7 NMAC prior to discharging to a conventional disposal system.

Q. The minimum liquid capacity of a septic tank shall be determined as follows:

(1) for residential units, the liquid capacity shall be based on the number of bedrooms using Table 201.2; and

(2) for commercial units, the liquid capacity shall be based on the number of plumbing fixture units using Table 201.2; or

(3) if based on flows calculated from Table 201.1 or from estimated design flows pursuant to Paragraphs (2), (3), (4) or (5) of Subsection P of 20.7.3.201 NMAC, the minimum liquid capacity shall be 2.5 times the design flow, whichever is greater.

Table 201.2: Capacity of septic tanks

Single family dwellings, number of bedrooms Other uses maximum fixture units* Minimum septic tank capacity in gallons served
1 10 750
2 - 3 12 1000
4 15 1200
5 - 6 20 1500
7 - 9 27 2000
29 2250
32 2500
35 2750

* 100 fixture units or less are equal to 31.1 gallons per fixture unit.

R. Waste from a water softener unit shall comply with the following.

(1) Softener waste may be discharged to a conventional treatment unit. If the waste is not discharged to the treatment unit, the waste may be disposed in accordance with other applicable regulations.

(2) For new construction utilizing an advanced treatment system, the softener waste shall not be discharged to the advanced treatment unit. The softener waste shall bypass the advanced treatment unit and discharge directly to the drainfield or be disposed of in some manner acceptable to the department and meets all other state and local regulations.

(3) If a water softener unit is installed at an existing residential or commercial unit utilizing an advanced treatment unit:
(a) the current liquid waste permit shall be amended to reflect the installation;

(b) a written notice shall be submitted to the maintenance service provider of the advanced treatment unit; and

(c) either a demand-initiated regeneration control device (DIR device) shall be installed or the softener waste shall bypass the advanced treatment unit.

(4) If an advanced treatment unit is to be installed at an existing residential or commercial unit with an existing water softener, the installation shall be done in accordance with the permit.

Disclaimer: These regulations may not be the most recent version. New Mexico may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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