Consecutive and Purchased-Water System Obligations

Buying finished water from another public water system does not retire your PWSID. You are a consecutive system, sometimes called a purchased-water system, and you still owe the samples, notices, and reports that attach to the customers you serve.

This page is the split: what typically stays with the wholesale seller, what stays with the buyer, and how to find the contract language plus the seller's PWSID. Confirm the split with your state primacy agency. This isn't legal advice.

Wholesale vs consecutive

40 CFR 141.2 defines both terms. A wholesale system treats source water as needed to produce finished water, then delivers some or all of that finished water to another public water system. A consecutive system receives some or all of its finished water from one or more wholesale systems. Delivery can be a direct interconnection or a path through another consecutive system's pipes.

Together they are a combined distribution system. A town on a regional plant, a mobile home park on a city master meter, a rural district that resells to a school: two PWSIDs, one pipe, two files. Buying all of your water, or mixing a well with an emergency interconnect, does not delete the duties that attach to the water you serve.

What 40 CFR 141.29 actually does

When one public water system supplies water to another, the state may modify the monitoring requirements in 40 CFR Part 141 to the extent the interconnection justifies treating the systems as a single system for monitoring purposes. Any modified schedule has to be specified by the state and concurred in by the EPA Administrator.

That is a state decision, not a handshake between operators. States may modify monitoring. They may not modify the compliance duties themselves. Ask the primacy agency, in writing, which samples sit on your PWSID this year. Don't copy a neighboring district's split.

Who samples for what

There is no single national spreadsheet that assigns every analyte. The pattern most states use, unless they have issued a 141.29 modification, looks like this:

• Usually the seller. Source-water monitoring: inorganics, synthetics, volatiles, radionuclides, and entry-point nitrate at the plant that treats the source. Surface Water Treatment Rule work, if they treat surface water or GWUDI. Anything that is a property of the source, not of your pipes.
• Usually the buyer. Revised Total Coliform Rule samples in your distribution. Lead and copper at your customers' taps. Disinfectant residual in your pipes. Often Stage 2 disinfection byproducts (TTHM and HAA5) at sites in your distribution, because those form in time and in your storage.
• Shared on paper, not on the tap. The seller's source results have to reach you in time for your CCR and for any notice you owe. That is data transfer, not the seller pulling your coliform sample.

Lead and copper is the one small systems misread most often. The action level is measured at the taps of the people you serve. A clean result at the wholesale plant does not stand in for your tap set. See Lead and copper action level. Coliform frequency is yours too: RTCR total coliform sampling frequency. If TTHM or HAA5 is assigned to your distribution, disinfection byproducts is the violation page, not the seller's.

If you add chlorine at a booster, or you operate storage, you have created water-quality conditions the seller does not control. Residual, DBPs, and storage integrity follow the operator who runs those assets. Confirm the assignment. Don't guess from an old invoice.

The CCR still belongs to the community system that serves customers

If you are a community water system, you deliver a Consumer Confidence Report to your customers. Buying the water does not move that duty to the seller. The wholesale system is not responsible for writing your CCR, and it is not responsible for the contaminants you monitor in your own distribution (coliform, lead, copper, and often TTHM and HAA5).

What the seller does owe is the source and compliance data you can't generate yourself. Under 40 CFR 141.152(d), a wholesale system must deliver the applicable water-quality information to each consecutive system no later than April 1, unless the two systems agree on a different date and put that date in a contract. April 1 exists so you can still hit the July 1 CCR delivery date. If the data arrives in June, that is a contract and a rule problem, not a reason to skip July 1.

You may reprint the seller's CCR with your letterhead and your extra data, or attach a cover letter to their report. Either way, the consecutive community system must get a complete report to its customers and certify delivery to the state. See What is a CCR and How to deliver and certify your CCR.

How to find the contract language and the seller's PWSID

The split lives in two places: the state's monitoring schedule for your PWSID, and the written agreement with the seller. Pull both. Don't rely on a memory of what the previous operator said at the tank site.

Look for a wholesale agreement, water-purchase contract, interconnection agreement, or master-meter contract. Read for:

• Who collects which samples, and who pays the lab.
• Who reports results to the state, and under which PWSID.
• The April 1 (or other) date for CCR data.
• Who issues public notice, and to whose customers, if the seller has a source exceedance.
• What happens on an emergency interconnect, a seasonal purchase, or a mix of purchased water and your own well.

The seller's PWSID should appear on invoices, on the state's inventory, on the seller's CCR, and on your own last CCR. If it doesn't, look the seller up by name and write the identifier on your sample siting plan and in the contract file. PWSID lookup is the free national search. Put both PWSIDs in the subject line of every email you send the state about purchased water.

If the contract is silent on monitoring, the state's schedule controls. Ask the primacy agency to put the assignment in writing. A missing clause is not permission to skip lead tap samples because "the city already does that."

Public notice and your own record

Your customers are yours. A coliform issue in your distribution, or a lead action-level exceedance at your taps, is your notice. If the seller has a source MCL and you serve that water, ask the state what notice you owe your own customers. Don't wait for the seller's press release. See SDWA public notice tiers.

Your SDWIS record is also yours. A monitoring violation on the consecutive PWSID does not move to the wholesale file because you buy the water. Read your own record: How to read your SDWIS violation record.

FAQ

If I buy all of my water, do I still need a PWSID?

Yes. A consecutive system is a public water system. It has its own PWSID, its own monitoring schedule, and its own compliance record. The seller's identifier does not replace yours.

Does the seller write my CCR?

Not unless you hired them to. Even then, the community consecutive system is responsible for a complete report reaching its customers and for certification to the state. The seller must send you the source data, usually by April 1, unless the contract sets another date.

Can the state treat us and the seller as one system for sampling?

Yes, under 40 CFR 141.29, if the interconnection justifies it and EPA concurs. That is a written state modification, not a verbal understanding. Ask for the current schedule on your PWSID before you drop a sample the seller "already takes."

Who samples lead and copper in a purchased-water system?

Usually you do, at your customers' taps. Lead and copper are distribution and plumbing findings. A clean result at the wholesale plant is not your tap set. Confirm the assignment with the state.

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Orevant provides compliance information tools. This page isn't legal advice. Confirm monitoring, CCR data dates, and the purchase-contract split with your state primacy agency.