E. coli / Total Coliform Testing · NJ NELAP · SM 9223B · Colilert-18

E. coli in Drinking Water
Is A Public Health Emergency.

Presence/Absence · MPN Enumeration · SDWA compliance · NJ NELAP certified. Results in 24–48 hours.

NJ NELAP SM 9223B Colilert-18 SDWA Compliant 24–48 hr TAT

Order Sample Kit → Submit a CoC

The Hazard

What Are Coliform Bacteria?

Total coliform is an indicator. E. coli is the confirmation of fecal contamination. Under the Revised Total Coliform Rule, a positive result is a trigger for follow-up — not, by itself, an automatic violation.

An E. coli MCL violation is acute — once determined, it requires Tier 1 public notification within 24 hours. But a routine positive first triggers repeat sampling; the violation is determined by those repeats, not by the single result.

Total Coliform

A broad group of bacteria used as indicator organisms. Their presence suggests a pathway for fecal contamination — even if no direct fecal source has been confirmed.

No MCL — the 2016 Revised Total Coliform Rule replaced it with a treatment technique
A positive routine sample requires three repeats within 24 hours of notification
Level 1 assessment triggered by repeat positives — complete and submit within 30 days

E. coli

The confirmatory indicator of fecal contamination. E. coli originates in the intestinal tracts of animals and humans — a positive is treated seriously and acted on quickly.

MCL is trigger-based — a routine positive requires repeat sampling before a violation is determined
Once determined, an E. coli violation is acute: Tier 1 public notification within 24 hours
Follow your primacy agency’s direction on notification and response

Recreational Water

EPA uses E. coli as the primary fecal indicator for freshwater. Testing supports beach closures and reopening decisions.

EPA 2012 RWQC: 126 CFU/100 mL geometric mean (freshwater)
Statistical threshold value: 410 CFU/100 mL
NJ recreational water quality monitoring program

SM 9223B using Colilert/Colilert-18 is the EPA-accepted method for simultaneous detection of total coliform and E. coli in a single sample.

Analytical Methods

Two Tests. One Sample. Simultaneous Results.

SM 9223B detects total coliform and E. coli simultaneously using ONPG-MUG (Colilert-18). Choose the format that matches your regulatory requirement.

Presence / Absence (P-A)

SM 9223B — ONPG-MUG (P-A)

SDWA Routine Monitoring

Best for

Municipal water systems · SDWA routine monitoring · Private well compliance screening

How it works

Single 100 mL sample. Positive/negative result. Yellow = total coliform positive. Fluorescent = E. coli positive.

Regulation

SDWA 40 CFR Part 141 · NJ DEP drinking water monitoring rules · EPA Method DW01

Turnaround

24–48 hours

Deliverable

P-A result for total coliform and E. coli, with the RTCR trigger and repeat-sampling guidance included.

MPN Enumeration (Multi-Well)

SM 9223B Multi-well — Colilert-18

Quantitative / Source Investigation

Best for

Source water investigation · Quantitative monitoring · Post-contamination event documentation

How it works

Quanti-Tray/2000 quantifies MPN per 100 mL. Provides count not just presence — essential for source tracking.

Regulation

EPA recreational water criteria · NJ recreational monitoring · Source water assessment programs

Turnaround

24–48 hours

Deliverable

MPN count per 100 mL for total coliform and E. coli. Suitable for recreational water reporting.

Decision Guide

Which Test Is Right for Your Situation?

Match your purpose to the correct method — before submitting.

Municipal water system — SDWA routine monitoring schedule SDWA compliance only requires P-A — a pass/fail result satisfies routine RTCR monitoring requirements.

Presence/Absence (P-A)

Private well — homeowner screening or NJ Private Well Testing Act SDWA does not apply to private wells — the NJ Private Well Testing Act and your local health department govern. P-A is the standard screening format; no quantification required.

Presence/Absence (P-A)

Post-positive follow-up — quantify contamination level after P-A positive MPN count quantifies severity and tracks remediation progress — essential for source identification.

MPN Enumeration

School or recreational water body — quantitative documentation needed EPA recreational water criteria require MPN counts — P-A alone doesn’t satisfy quantitative reporting.

MPN Enumeration

IH or consultant — full water quality assessment or litigation support P-A confirms presence, MPN quantifies concentration — together provide complete evidentiary record.

P-A + MPN (Combo)

E. coli results needed urgently? 24-hour TAT available. Submit a request →

Process

How It Works

From sample kit to actionable result in 24–48 hours.

Order Sample Kit

IRIS ships sterile, sodium thiosulfate-treated 120 mL sample bottles (for chlorinated water) or untreated bottles (unchlorinated), plus COC and pre-paid shipping label.

Order Kit →

Collect & Complete COC

Remove the aerator, disinfect the outlet, then flush 2–3 minutes before collecting 100 mL from a cold tap. This is the opposite of lead sampling — never flush “for LCRR.” Note chlorine residual, source type, and exact collection time on the Chain of Custody.

Ship Overnight

Ship immediately after collection. Public water system compliance: no more than 30 hours from collection to the start of incubation (recreational windows are shorter). Hold between 0 and 10°C — do not freeze.

Results in 24–48 hrs

P-A or MPN result with RTCR interpretation. NJ NELAP certified. If positive, the report includes repeat-sampling and notification guidance for your system type.

⚠

If you receive a positive result:

Public water systems: collect the required repeats within 24 hours of notification and contact your primacy agency — whether a violation exists depends on those repeats, so do not issue public notification before that determination unless your agency directs it. Private wells: stop using the water for drinking, cooking, and brushing teeth, and contact your local health department; boiling is an interim measure.

Sampling Resources

Download the Field Guide Before You Sample.

Bacteriological sampling is unforgiving on technique — the guide covers tap selection, disinfection and flushing, fill line, hold times, and what a positive actually means.

E. coli & Total Coliform Sample Collection Field Guide

Two-page field guide: kit checklist, tap preparation and flushing, chain-of-custody fields, chill-and-ship windows, and how to read a positive under the Revised Total Coliform Rule.

Download PDF

PDF · SM 9223B, Colilert-18 · Rev. 2026-07

NJ NELAP · SM 9223B · Colilert-18 · SDWA Compliant

Order Your
Bacterial Testing Kit.

Total coliform · E. coli · Presence/Absence or MPN enumeration. Results in 24–48 hours. NJ NELAP certified.

Sterile sample bottles COC form included Pre-paid FedEx label 24-hr TAT available