N.M. Code R. § 20.7.3.301
B. The date of record for a lot shall be considered to be either:
(1) the date of legal recording in the county clerk's office or validation by other means associated with the most recent change in lot size or boundaries; or
(2) for those lots in subdivisions having received final approval from governments having jurisdiction therein prior to February 1, 1990, such date of record shall be two and one-half years from the date of final government approval or July 1, 1992, whichever occurs first.
E. Table 301.1 lists the minimum lot sizes required for typical flow rates for conventional treatment systems for lots with a date of record of February 1, 1990 or later.
Table 301.1
TOTAL DESIGN FLOW (gallons per day) MINIMUM LOT SIZE (acres) if !supportMisalignedRows endif if !supportMisalignedRows endif 375 or less 0.75 if !supportMisalignedRows endif 440 0.88 if !supportMisalignedRows endif 500 1.00 if !supportMisalignedRows endif 750 1.50 if !supportMisalignedRows endif 1125 2.25 if !supportMisalignedRows endif 1500 3.00 if !supportMisalignedRows endif 1875 3.75 if !supportMisalignedRows endif 2000 4.00 if !supportMisalignedRows endif
TOTAL DESIGN FLOW (gallons per day)
MINIMUM LOT SIZE (acres)
375 or less
0.75
440
0.88
500
1.00
750
1.50
1125
2.25
1500
3.00
1875
3.75
2000
4.00
F. The department may issue permits for lots not complying with Subsection C of 20.7.3.301 NMAC for areas the department has identified and mapped where groundwater is not at risk from nitrogen loading from on-site liquid waste systems. The following hydrogeologic conditions may be considered when determining if groundwater is not at risk:
(1) groundwater does not exist;
(2) the uppermost groundwater contains a total dissolved solids concentration greater than 10,000 milligrams per liter;
(3) the uppermost groundwater occurs under confined conditions;
(4) the uppermost groundwater occurs at a depth between 400 and 600 feet with one or more geologic strata in the vadose zone that may act as a capillary barrier; and
(5) the uppermost groundwater occurs at a depth greater than 600 feet.
In areas that have not been identified and mapped by the department, the applicant must demonstrate one of the above conditions exists prior to the issuance of a permit.
G. The following Table 301.2 summarizes the minimum lot size requirements, in acres, and permissible design flows in effect prior to February 1, 1990 and is for the purpose of determining the requirements existing at the time of initial installation or most recent permitted modification.
Table 301.2
RECORD DATE 01/01/60 to 11/01/73 11/01/73 to 09/07/79* 09/07/79 to 03/01/80 03/01/80 to 11/09/85 11/09/85 to 02/01/90 Minimum Lot Size Soil Group ** Min. Lot Size Total Design Flow (gpd) Min. Lot Size Total Design Flow (gpd) Min. Lot Size Total Design Flow (gpd) Min. Lot Size OFF-SITE WATER** 0.25*** A 0.50 0-1000 0.50 0-375 0.33 0-375 0.33 B 0.75 1000- 1500 1.00 376- 1000 0.50 376- 750 0.50 C 1.00 1500- 2000 1.25 1000- 1500 1.00 750- 1125 1.00 D **** 1501- 2000 1.25 1126- 1500 1.25 1501- 2000 1.75 ON-SITE WATER** 0.50*** A 0.75 0-1000 0.75 0-1000 0.75 0-375 0.75 B 1.00 1000- 1500 1.25 1000- 1500 1.25 376- 750 1.50 C 1.25 1500- 2000 1.70 1501- 2000 1.70 750- 1125 2.00 D **** 1126- 1500 2.75 1501- 2000 3.50
RECORD DATE
01/01/60
to
11/01/73
11/01/73
to
09/07/79*
09/07/79
to
03/01/80
03/01/80
to
11/09/85
11/09/85
to
02/01/90
Minimum
Lot Size
Soil
Group
**
Min.
Lot
Size
Total
Design
Flow
(gpd)
Min.
Lot
Size
Total
Design
Flow
(gpd)
Min.
Lot
Size
Total
Design
Flow
(gpd)
Min.
Lot
Size
OFF-SITE
WATER**
0.25***
A
0.50
0-1000
0.50
0-375
0.33
0-375
0.33
B
0.75
1000-
1500
1.00
376-
1000
0.50
376-
750
0.50
C
1.00
1500-
2000
1.25
1000-
1500
1.00
750-
1125
1.00
D
****
1501-
2000
1.25
1126-
1500
1.25
1501-
2000
1.75
ON-SITE
WATER**
0.50***
A
0.75
0-1000
0.75
0-1000
0.75
0-375
0.75
B
1.00
1000-
1500
1.25
1000-
1500
1.25
376-
750
1.50
C
1.25
1500-
2000
1.70
1501-
2000
1.70
750-
1125
2.00
D
****
1126-
1500
2.75
1501-
2000
3.50
(1) * The maximum total design flow was 1,000 gpd for the lot sizes shown.
(2) ** See Subsection H of 20.7.3.301 NMAC.
(3) *** These requirements applied to lots in subdivisions that were required at the time of subdivision to obtain state health department review and approval.
(4) **** No on-site liquid waste disposal to soil allowed.
(5) NOTE: Roadways were excluded from figuring lot sizes from 11/09/85 to 9/1/13.
H. The following Table 301.3 lists the soil types for lot size determinations for the period November 1, 1973 to September 7, 1979: The minimum lot size required for the location of an individual liquid waste disposal system is determined by the most limiting soil group under which any soil characteristic falls.
Table 301.3
SOIL CHARACTERISTICS A Slight Limitations B Slight Limitations C Moderate Limitations D Severe Limitations 1. SOIL DEPTH (depth to bedrock, in feet) More than 6 and More than 6 and 4 - 6 or Less than 4 or 2. PERCOLATION RATE (rate of percolation of water into soil in minutes per inch) 0 - 15 and 16 - 30 and 31 - 60 or More than 60 or 3. SEASONAL WATER TABLE (depth to shallowest water table during the year, in feet) More than 12 and More than 12 and 4 - 12 or Less than 4 or 4. SLOPE (incline of the land surface, in percent) 0 - 8 and 0 - 8 and 8 - 25 or More than 25 or 5. FLOODING POTENTIAL (overflow frequency, in years) None None No more than 1 in 25 More than 1 in 25
SOIL
CHARACTERISTICS
A
Slight
Limitations
B
Slight
Limitations
C
Moderate
Limitations
D
Severe
Limitations
1.
SOIL DEPTH
(depth to bedrock, in feet)
More than 6
and
More than 6
and
4 - 6
or
Less than 4
or
2.
PERCOLATION RATE
(rate of percolation of water into soil in minutes per inch)
0 - 15
and
16 - 30
and
31 - 60
or
More than 60
or
3.
SEASONAL WATER TABLE
(depth to shallowest water table during the year, in feet)
More than 12
and
More than 12
and
4 - 12
or
Less than 4
or
4.
SLOPE
(incline of the land surface, in percent)
0 - 8
and
0 - 8
and
8 - 25
or
More than 25
or
5.
FLOODING POTENTIAL
(overflow frequency,
in years)
None
None
No more than
1 in 25
More than
1 in 25
[20.7.3.301 NMAC - Rp, 20.7.3.301 NMAC, 9/1/13; A, 9/1/13]