The New Mexico Environment Department The Department’s Mission is to provide the highest quality of life throughout the state by promoting a safe, clean, and productive environment.

The New Liquid Waste Regulations Changes in Construction Requirements Changes in Tank Requirements Lot Size Factors

Construction Requirement Changes  Maximum Trench Length: 150 Feet.  Minimum Amount of Gravel Under Leach Line: 6 Inches.*  Minimum Trench Width: 1 Foot.  No Tree Setback.  Geotextile Fabric Over Leach Line: No Gravel Required to Cover.*  Change: *Up to one foot less gravel.

Construction Requirement Changes  Maximum depth of trench: 6 feet.  Minimum amount of trench cover: 9 inches.  Lateral trenches: Only “D” boxes allowed, no tees. “D” boxes to be internally baffled and internally coated with bituminous material. All leveling and stabilizing requirements still in effect.  Lateral leach lines to begin a minimum of five feet from “D” boxes. (Not new, but of new importance.)

Construction Requirement Changes  Seven linear feet of trench credit allowed. Examples: One foot trench plus 3 extra feet of gravel=7 ft. (new)* Two foot trench plus 21/2 extra feet of gravel=7 ft. Three foot trench plus 2 extra feet of gravel=7 ft. Changes: *more sidewall credit.

Why These Construction Changes?  It has been recognized that we need to rely more on sidewall absorption than on bottom absorption. Also note that the trench depth restriction and reduction of top cover allow more evapotranspiration. These construction design changes allow more liquid to go “sideways” and “up”, rather than “down” towards the water table. They also provide better oxygenation of the effluent. New home stub-outs: discuss.

New Field Sizing`  Multiply GPD by 2 Example: Three bedroom home = 375 GPD x 2 = 750 sq. ft. Etc. ATU’s and proprietary leach field components each allow a 30% leach field reduction, but not both. An ATU with Infiltrators does not get 60% reduction.

Seepage Pits  Seepage Pits may be installed only with a variance from Santa Fe.

Septic Tank Requirements  Manhole covers to be 22 inches at smallest dimension. (Not new.)  All tanks will be installed with manhole risers.  Manhole covers must weigh a minimum of 58 LBS, or be lockable. (Safety against entry by children)  Risers must have child-proof cover retainers, or internal safety devices.  All tanks must have an effluent filter installed, internal or external.

Undeveloped Lots, Platted before 2/1/90  No conventional septic systems on lots smaller than 0.5 acre.  No conventional septic systems on lots smaller than 0.75 acre in areas with depth to ground water 100 feet or less, or within 200’ of public well.

Small Lot Grandfathering Old rule allowed conventional septic systems on lots less than 0.75 acre if platted prior to 2/2/90.

Revised Lot Size Rules Record DateMinimum Lot Size (acre) 2/1/90 to present0.75 Before 2/1/90, developed lot lot size in effect on record date Before 2/1/90, undeveloped lot 0.5 to 0.75, depending on depth to GW, water source, proximity to public well

Greater than 600’ Depth to Ground Water: Minimum lot size of 0.5 acre, no sunset provision. Undeveloped Lots, Platted before 2/1/90

 Sunset Provisions for ’ Depth to Ground Water:  3 year sunset period for lots with on-site wells, not within 200’ of public well  5 year sunset period for lots with public water system, not within 200’ of public well  No conventional septic systems on lots smaller than 0.5 acre.

Greater than 600’ Depth to Ground Water: Minimum lot size of 0.5 acre, no sunset provision. Undeveloped Lots, Platted before 2/1/90

Un-permitted Systems Installed prior to 2/1/02 – certificate of registration for continued operation issued if: system pumped and inspected; system appears to be functioning properly; and the fee is paid.

Un-permitted Systems Installed after 2/1/02 – may be permitted if: system is fully exposed and inspected; system, upon inspection, meets all regulatory requirements; and fee and penalty are paid.

Transfer of Permits Conventional Systems  Permit transferable with property if system inspected and evaluated  No change of ownership notification required Advanced Systems  Permit transferable with property if system inspected and evaluated  New owner must notify NMED and provide valid maintenance contract

Is the Lot Too Small? – The Kicker  When a leach field is built on any lot, There must be enough available space remaining on the lot, including all setbacks, to build a replacement field should the first field fail.