For Drinking Water Operator Certification study, a common practical question is how long a public water system has to keep its records. The general rule is 40 CFR 141.33, Record maintenance, in Subpart D of the national primary drinking water regulations. This explainer reads that section, and the Consumer Confidence Report retention rule in 141.155, as they stand in the eCFR. It does not describe a rule change. Your State's drinking water program may also have rules, so check with your State as well.
Who must keep records, and where?
The owner or operator of the system. 141.33 opens: "Any owner or operator of a public water system subject to the provisions of this part shall retain on its premises or at a convenient location near its premises the following records". The periods below are minimums: the section says "not less than" for most of them.
How long are lab analysis records kept?
It depends on the kind of analysis. 141.33(a) states: "Records of microbiological analyses and turbidity analyses made pursuant to this part shall be kept for not less than 5 years. Records of chemical analyses made pursuant to this part shall be kept for not less than 10 years."
Must the system keep the original lab reports?
No. Under 141.33(a), "Actual laboratory reports may be kept, or data may be transferred to tabular summaries, provided that the following information is included":
- "The date, place, and time of sampling, and the name of the person who collected the sample"
- "Identification of the sample as to whether it was a routine distribution system sample, check sample, raw or process water sample or other special purpose sample"
- "Date of analysis"
- "Laboratory and person responsible for performing analysis"
- "The analytical technique/method used"
- "The results of the analysis"
How long are violation records kept?
Records of fixing a violation are counted from the last action, not from the violation itself. 141.33(b) states: "Records of action taken by the system to correct violations of primary drinking water regulations shall be kept for a period not less than 3 years after the last action taken with respect to the particular violation involved."
What about sanitary survey reports?
Ten years after the survey is completed, whoever did it. 141.33(c) covers "Copies of any written reports, summaries or communications relating to sanitary surveys of the system conducted by the system itself, by a private consultant, or by any local, State or Federal agency", which "shall be kept for a period not less than 10 years after completion of the sanitary survey involved."
How long are variance and exemption records kept?
The clock starts when the variance or exemption expires. Under 141.33(d), "Records concerning a variance or exemption granted to the system shall be kept for a period ending not less than 5 years following the expiration of such variance or exemption."
What about public notices and certifications?
Three years. 141.33(e) states: "Copies of public notices issued pursuant to subpart Q of this part and certifications made to the primacy agency pursuant to § 141.31 must be kept for three years after issuance."
How long are monitoring plans kept?
As long as the analyses taken under them. 141.33(f) states that "Copies of monitoring plans developed pursuant to this part shall be kept for the same period of time as the records of analyses taken under the plan are required to be kept under paragraph (a) of this section, except as specified elsewhere in this part." Other subparts of Part 141 may set their own record rules; this explainer covers only 141.33 and 141.155.
How long must a system keep its Consumer Confidence Report?
At least 3 years. 141.155(h) states: "Any system subject to this subpart must retain copies of its Consumer Confidence Report for no less than 3 years." That retention rule is in both the version of 141.155 that applies until December 31, 2026 and the version that applies from January 1, 2027, as our Consumer Confidence Report deadlines explainer explains, along with which version applies when.
The version that applies from January 1, 2027 (the current eCFR text) also has a rule for reports posted online, which applies from that date. 141.155(a)(4) states: "Systems that use a publicly available website to provide reports must maintain public access to the report for no less than 3 years."
Quick reference
- Microbiological and turbidity analyses: not less than 5 years (141.33(a)).
- Chemical analyses: not less than 10 years (141.33(a)).
- Actions to correct violations: not less than 3 years after the last action (141.33(b)).
- Sanitary survey reports: not less than 10 years after completion (141.33(c)).
- Variances and exemptions: not less than 5 years after expiration (141.33(d)).
- Public notices and 141.31 certifications: three years after issuance (141.33(e)).
- Monitoring plans: same period as the analyses under the plan (141.33(f)).
- Consumer Confidence Reports: no less than 3 years (141.155(h)).
Where to study this
Our study guides do not cover 141.33 itself. Public notices under Subpart Q are covered in the public notification study guide, coliform sampling in the total coliform study guide, and system types in the systems and definitions study guide. See the drinking water operator hub for all practice tests.