Regulatory Standard Database

LimnaFlow ships with a complete set of federal regulatory standards that environmental consultants reference daily. This includes EPA National Primary Drinking Water Regulations (MCLs for approximately 90 contaminants) with MCLGs for reference, EPA Secondary Maximum Contaminant Levels (SMCLs) for aesthetic parameters like iron, manganese, and sulfate, and EPA Action Levels for lead (15 ppb) and copper (1.3 mg/L) under the Lead and Copper Rule.

For site assessment work, the database includes EPA Regional Screening Levels (RSLs) for tap water, residential soil, and industrial soil. RSLs are updated within 7 days of each EPA semi-annual release (typically May and November). EPA PFAS MCLs — PFOA at 4 ppt, PFOS at 4 ppt, plus MCLs for PFHxS, PFNA, and HFPO-DA (GenX) — are maintained as EPA finalizes or revises these values.

Every state has standards that differ from or are more stringent than federal values. LimnaFlow maintains state-specific standards across four categories: state drinking water MCLs (e.g., New Jersey arsenic at 5 ppb vs. federal 10 ppb, California perchlorate at 6 ppb, Massachusetts manganese at 0.3 mg/L), state groundwater quality standards and cleanup criteria (NJ Ground Water Quality Standards, MA MCP Method 1 GW-1 Standards, CA Environmental Screening Levels, FL Groundwater Cleanup Target Levels, PA Medium-Specific Concentrations), state PFAS standards where more stringent than federal, and state surface water quality standards for common discharge parameters.

All 50 states are covered. When you create a project and select your jurisdiction, LimnaFlow automatically surfaces the applicable state standards alongside federal values so you never accidentally screen against the wrong set.

Every standard value in the database carries full metadata: analyte name, CAS number, standard value, units, standard type (MCL, RSL, state cleanup, action level), applicable matrix (groundwater, drinking water, soil), effective date, superseded date if applicable, source citation with regulation number and Federal Register citation, and a link to the source document.

This metadata serves two purposes. First, it enables accurate screening — the comparison engine uses CAS number, matrix, and standard type to match the right standard to the right result. Second, it provides defensibility — every standard value in your exceedance table can be traced back to its regulatory source with a specific citation, which is essential when your tables appear in compliance reports submitted to regulatory agencies.

When a standard changes, LimnaFlow preserves both the old and new values with their respective effective date ranges. This matters because environmental compliance is often assessed retrospectively — you may need to screen historical data against the standards that were in effect at the time of sampling, not today's standards.

You can select a standard set effective as of a specific date for any project. If you are preparing a compliance report for sampling conducted in 2024, you can apply the standards that were effective during that period even if they have since been updated. The versioning system tracks every change with the date it took effect and the date it was superseded.

When standards change — whether EPA updates RSLs, a state revises its groundwater criteria, or new PFAS MCLs take effect — LimnaFlow notifies affected users. If you have active projects in New Jersey and NJ updates its GWQS, you receive an in-app notification listing which analytes have new standard values and how your active projects are affected. This eliminates the risk of screening against outdated values without realizing it.

A public Standard Coverage Dashboard shows which standards are loaded, when each was last verified against the source regulation, and the date of the next scheduled verification. This transparency lets you and your clients confirm that the standards database is current — a level of traceability that Excel lookup tables cannot provide.