A. Design and operations guidelines. To reduce risks of water contamination, the following design and operations guidelines shall be observed wherever germane in all new nonresidential construction.

(1) Safeguards. Provisions shall be made to protect against hazardous materials discharge or loss through corrosion, accidental damage, spillage or vandalism through such measures as provision for spill control in the vicinity of chemical or fuel delivery points, secure storage areas for hazardous materials and indoor storage provisions for corrodible or dissolvable materials.

(2) Disposal. Provisions shall be made to assure that any waste disposed on the site shall contain no hazardous materials in concentrations substantially greater than associated with normal household use.

(3) Drainage. Floor or lavatory drainage shall be directed to an impervious retention facility for controlled removal. Provision shall be made for on-site recharge of all stormwater runoff from impervious surfaces unless, following consultation with the Conservation Commission, the Building Inspector determines that either recharge is infeasible because of site conditions or is undesirable because of uncontrollable risks to water quality from such recharge. Recharge shall be by surface infiltration through vegetative surfaces unless otherwise approved by the Building Inspector following consultation with the Conservation Commission. Dry wells shall be used only where other methods are infeasible and shall employ oil, grease and sediment traps. Drainage from loading and unloading areas for hazardous materials shall be separately collected for safe disposal.

B. Uses requiring special permits.

(1) The following shall be allowed only if granted a special permit from the special permit granting authority:

(a) Waste generation requiring the obtaining of an Environmental Protection Agency identification number, except for small quantity generators, as defined under DEQE regulations, 310 CMR 30.351.

(b) On-site sewage disposal having an estimated sewage flow greater than fifteen thousand (15,000) gallons per day, regardless of location, or greater than one thousand five hundred (1,500) gallons per day if within five hundred (500) feet of any surface water body.

(c) Rendering impervious more than seventy-five percent (75%) of lot area.

(d) Except for single-family dwellings, on-site sewage disposal systems having an estimated sewage flow exceeding one hundred twenty (120) gallons per day per ten thousand (10,000) square feet of lot area.

(e) Discharge to surface water requiring a permit under 314 CMR 3.00 (NPDES permit).

(2) Change in activity resulting in crossing any of the thresholds of B(1)(a) through (d) shall constitute a change of use requiring a special permit.

C. Special permit process.

(1) Authority and procedure. The special permit granting authority (SPGA) shall be the Board of Appeals. Upon receipt of the special permit application, the SPGA shall transmit one (1) copy each to the Planning Board, the Conservation Commission, the Board of Health and the Building Inspector for their written recommendations. Failure to respond within thirty-five (35) days of transmittal shall indicate approval by said agencies.

(2) Submittals. In applying for a special permit under this section, the information listed below shall be submitted unless the Board of Appeals, prior to formal application, determines that certain of these items are not germane:

(a) A complete list of all chemicals, pesticides, fuels or other potentially hazardous materials to be used or stored on the premises in quantities greater than associated with normal household use, accompanied by a description of the measures proposed to protect all storage containers or facilities from vandalism, corrosion and leakage and to provide for control
of spills.

(b) A description of potentially hazardous wastes to be generated, including storage and disposal methods as in Subsection C(2)(a) above.

(c) For aboveground storage of hazardous materials or wastes, evidence of qualified professional supervision of design and installation of such storage facilities or containers.

(d) For disposal on-site of domestic wastewater with an estimated sewage flow greater than fifteen thousand (15,000) gallons per day, evidence of qualified professional supervision of design and installation, including an assessment of nitrate, phosphate and coliform bacteria impact on groundwater quality.

(3) Special permit criteria. Special permits under this section shall be granted only if the SPGA determines that there is adequate assurance that there will be no violation of the Massachusetts Surface Water Quality Standards (314 CMR 4.00) and that groundwater quality resulting from on-site waste disposal, other operations on-site and natural recharge will not fall below federal or state standards for drinking water when averaged over the boundaries of the site or, if existing groundwater quality is already below those standards, on-site disposal or operations will result in no further deterioration and only if the SPGA determines that proposed control and response measures adequately and reliably mitigate risk to groundwater quality resulting from accident or system failure. In its decision, the SPGA shall explain any departures from the recommendations of other town agencies in its decision.
(4) Conditions. Special permits shall be granted only subject to such conditions as are necessary to assure adequate safeguarding of water quality, which may include the following, among others:

(a) Monitoring wells to be located downgradient of potential pollution sources, with periodic sampling to be provided to the Board of Health at the owner's expense.

(b) Pollutant source reduction, including limitations on use of parking area deicing materials and periodic cleaning or renovation of pollution control devices, such as catch basin sumps.