Water Sample Collection for a Customer Complaint

Purpose

A laboratory analyses what is in the bottle. It cannot tell you where that water was standing, how long it stood, which tap it came from, or whether the tech ran the faucet first. Those decisions are made in the field by the person filling the bottle, and together they decide which question the result can answer. A bottle filled without them is not a weak result, it is an uninterpretable one, and the shop pays for it twice.

Scope

Covers collecting water samples on a customer complaint at a house, duplex, small retail unit, small restaurant or office, including the sequential profile used to locate which length of pipe is releasing.

Does not cover the diagnostic visit that decides whether sampling is the right move at all, owned by the water quality complaint visit SOP, nor the flush sampling after a service line replacement, which runs its own protocol. Does not cover the water system's own compliance monitoring, and does not cover turning a result into a statement about whether the water is safe to drink, which belongs to the laboratory and the health authority.

Roles and responsibilities

Procedure

1. Write the question the result must answer before anyone orders a bottle. Acceptance: a written question and a named analyte list on the ticket before the set is ordered, because the analyte fixes the bottle, the preservative and the hold time. What wrong looks like: "test the water", a general panel answering no complaint. Stop rule: a reported illness or health concern routes to the water system and the health authority the same day and the sampling conversation stops. Hazard: none, a desk decision - and nobody offers an opinion on whether the water is safe to drink at any point in this procedure.
2. Order the set from a laboratory certified for those analytes and read its instruction sheet on site. Acceptance: certification confirmed per analyte, seals intact, preservative present where the analyte needs one, every hold time copied onto the protocol sheet - metals are commonly acid-preserved with a long hold, while a bacteriological bottle carries a dechlorinating agent and a hold of hours, commonly 30 from collection. What wrong looks like: a bottle rinsed out on site, discarding the preservative. Stop rule: broken seal, missing preservative or expired hold and the bottle is not filled. Hazard: acid preservative burns skin and eyes, so never decant it or pour it off to make room, and hold the cap by its outside.
3. Set up the stagnation the protocol requires and prove it held. Acceptance: a stagnation inside the protocol's floor and ceiling, from the occupant's stated last water use, that instruction left in writing the day before. The federal lead protocol uses a six hour minimum with an upper limit, and the same logic governs any first-draw comparison. What wrong looks like: an occupant who ran a shower at 5 a.m. and did not count it, turning a first draw into a partly flushed sample that reads low. Stop rule: stagnation short of the floor abandons the run, bottles unfilled. Hazard: none, an interview at the door - but ask about appliances, since an ice maker or a recirculation pump on a timer breaks stagnation with nobody touching a tap.
4. Choose the tap and leave it exactly as the household uses it. Acceptance: a cold tap the family drinks from, usually the kitchen, aerator left in place for a lead first draw because the federal protocol collects water as the household would, and any garden hose removed where a bib is used. What wrong looks like: pulling the aerator or pre-running the tap, both of which destroy the thing being measured. Stop rule: where a point-of-use filter sits on that tap, bypass it or sample upstream and write that on the bottle, since a filtered sample labeled as a tap sample is a false negative on the pipe. Hazard: reaching behind a sink puts a hand beside a hot supply and a disposal, so kill the disposal at its breaker first and check the hot line with the back of the hand.
5. Draw the first bottle, and to locate the source keep drawing a sequential profile without a break. Sequential profiling fills numbered one-litre bottles back to back so each number maps to a position along the pipe. Acceptance: steady moderate flow, no pause and no valve movement between bottles, numbered in order, each pipe section's volume computed first. Gallons per foot is 0.0408 times the square of the inside diameter in inches, taken from the manufacturer's published dimensions rather than the nominal size; litres are gallons times 3.785. What wrong looks like: a gap while somebody finds a cap, letting the next slug sit and mixing the positions. Stop rule: any interruption voids the profile from that bottle on. Hazard: both hands stay full over a sink for minutes, so rack the filled bottles rather than lining a counter edge, and watch the drain before it floods the cabinet.
6. Draw the flushed comparison from the same tap and record the flush rather than describing it. Acceptance: flush duration in minutes and the flow it ran at, both measured, then the bottle filled and labeled flushed. What wrong looks like: a flushed sample from a different tap, which moves two variables at once and can no longer be paired with the first draw. Stop rule: report the pair as a comparison only when both bottles came from the same tap in the same visit. Hazard: a long flush at a single-lever tap runs hot if the handle drifts off centre, so set it full cold, re-check after a minute, and never flush into a vessel held in the hand.
7. Preserve, label and move the set inside the shortest hold time in it. Acceptance: every bottle carrying address, tap, date and clock time, stagnation, sequence position, and whether it is first draw, sequential or flushed; the custody form signed with those same times; the cooler at the laboratory's stated transport temperature. What wrong looks like: a custody form filled in at the shop from memory, putting two different times on one sample. Stop rule: schedule the set around its shortest hold time and recollect rather than send a bottle that cannot make it. Hazard: gel packs stacked on glass break bottles in a van, so pack them alongside, and handle a broken bottle with gloves and eye protection, since the preservative is still in it.
8. Restore everything the protocol made you shut, bypass or remove, and prove each restored function works. Acceptance: every stop back to full open, any bypassed point-of-use filter returned to service with a fresh cartridge dated on the housing, the disposal breaker back on, and each disturbed fixture run until it delivers clear water at full flow with no drip at the stop. What wrong looks like: a stop left half open, met a week later as low flow and read as damage from the visit. Stop rule: a weeping stop is replaced this visit, not snugged, since one that has not moved in years often will not reseat. Hazard: this puts pressure back with the customer at the sink, so open each stop slowly with the fixture open to bleed air, keep your face out of line with the outlet, and after hot-side work read delivered hot temperature with a thermometer in the stream to confirm the fixture's control still limits it.
9. Release the result only with its protocol attached, and never as a verdict. Acceptance: the report issued with the collection sheet so every number is read beside its tap, stagnation and position, and any regulatory figure quoted with its scope in the same sentence. The federal lead action level is a system-wide compliance trigger evaluated at the ninetieth percentile of the water system's own sampling pool, not a safe-or-unsafe line for one house, and the rule is mid-cycle, so pull the Lead and Copper Rule text your primacy agency has adopted rather than quoting a number from an article. What wrong looks like: a tech phoning ahead with "it came back fine". Stop rule: any health-effects question goes to the laboratory and the health authority in writing the same day. Hazard: none here; the exposure is a sentence, and it travels further than any repair.

The record this produces

One collection sheet per visit, stapled to the laboratory report on the customer record: the written question and analyte list; the laboratory and its certification; the stagnation claimed and the occupant's stated last use; the tap and whether a filter was bypassed; the bottle list with position, volume and clock time; the flush duration and measured flow; the pipe volume calculation with the inside diameters used and their source; the chain of custody number; and the restore checks.

The next tech reads the volume calculation to know which bottle sat in which pipe. The lead reads the stagnation line before any result reaches the customer. When a second sample is taken months later, the two sheets are the only thing making the results comparable.

One worked pass, including a failure

Duplex, 1952, metallic taste at the kitchen cold tap, service line material recorded as unknown. Question written at step 1: is metal being released in the buried service or in the interior piping. Analytes: lead and copper, acid-preserved metals bottles.

Volume computed before any bottle is filled. The interior run from the point of entry to the kitchen cold tap is 32 ft of 1/2 in type L copper, published inside diameter 0.545 in, so 0.0408 times 0.297 gives 0.0121 gal per ft; over 32 ft that is 0.388 gal, and 0.388 times 3.785 is 1.47 L. The buried service is 42 ft at a published inside diameter of 0.82 in, so 0.0408 times 0.672 gives 0.0274 gal per ft; over 42 ft that is 1.15 gal, or 4.36 L. The service therefore spans 1.47 L to 5.83 L of the draw. Six one-litre bottles cover it: bottle 1 is interior copper, bottle 2 straddles the transition, bottles 3 through 5 sit wholly in the service, and bottle 6 ends 0.17 L past it in the main.

The first visit fails at step 3. The occupant ran a bathroom sink at about 5 a.m. and did not count it, putting stagnation at roughly 3.5 hours against the six hour floor. Stop rule taken: no bottle filled, the set goes back sealed, the visit rebooks with the written instruction re-delivered and confirmed the evening before.

Second visit: stagnation 9 hours 10 minutes by the occupant's stated last use, inside the window. Aerator left on, no pre-flush, six bottles back to back at steady moderate flow, then the flushed comparison after 5 minutes at a measured 3.1 gpm from the same tap. Custody signed at the sink; the metals hold is long, so transport is scheduled that afternoon.

Results, as ratios against bottle 1: bottles 3, 4 and 5 come back between roughly three and four times bottle 1, bottle 2 sits between them, bottle 6 falls back near bottle 1, and the flushed bottle is lowest in the set. Concentration rises through exactly the bottles the volume calculation placed in the buried service and falls again in the one that reached the main, putting the release in the service line rather than the interior copper or the faucet. Step 8: kitchen stop reopened full, no weep, tap clear at full flow. Step 9: report and collection sheet issued together, the material verdict left where the service line material verification SOP puts it.

References

• Your water system's published lead program and consumer confidence report for the address, plus the current Lead and Copper Rule text as adopted by your primacy agency, which is mid-cycle and should be pulled rather than quoted from memory.
• A state-certified drinking water laboratory for the bottle set, preservation, hold times and chain of custody; their printed instruction governs where it differs from this SOP.
• Pipe manufacturer published dimensions for inside diameter, since nominal size is not inside diameter and the sequential profile is only as good as that figure.
• See related: the Plumbing water quality complaint visit SOP, the service line material verification methods SOP, and the post-replacement flushing and sampling SOP.