A walking,
drawing-based
cross-connection inventory.

What a survey is

A cross-connection hazard survey is a walking, fixture-by-fixture inventory of every place on a premises where the potable supply touches something else. The result is a numbered list — fixture, location, the substance on the other side of the touch, the hazard class per USC FCCCHR §3.4, the protection currently in place, and the protection required. The required and actual are reconciled in the final column.

What a survey finds

Across the 36 surveys we performed in 2024 and 2025, the average premises produced 18 line items, of which 4.2 were findings — protection required at a level above what was installed. The most common finding categories:

• Janitor closet mop sink with hose left coiled

  If the hose can reach a mop bucket, it can reach a chemical jug. The hose itself is a back-siphonage path. Protection required: SVB on the faucet, plus operational policy (uncoil the hose after use).

• Three-comp sink with pre-rinse spray nozzle below flood rim

  If the spray nozzle ends up in dishwater, the potable supply is in direct contact. Protection required: an SVB or AVB on the spray nozzle's supply.

• Soda-machine carbonator with brass check upstream

  Brass and CO₂ acid form lead carbonate over time. Old installs sometimes have a brass check between the city water and the carbonator. Protection required: replace the brass check with an RP, and route through a copper-free section of line.

• Lab faucet with attached aspirator

  An aspirator pulls air through a venturi; reversed pressure pulls beaker contents back through the faucet. Protection required: SVB on the lab faucet, plus an air-gap above the beaker rinse.

• Cooling tower with no upstream RP

  Cooling-tower makeup is high-hazard because the basin is dosed with biocide. If there's no RP on the makeup line, one is added.

Process

1. Pre-walk briefing with the property's facility manager. We collect any existing plans, last-known assembly list from MWW, and a key.
2. Walk-through, floor by floor, every fixture. Tester records each finding on a printed walk sheet (we do not use the iPad for surveys — physical paper is faster and survives spills).
3. Plan markup. Each finding is placed on the floor plan with a numbered marker.
4. Office synthesis. The walk sheet is digitized into the inventory table; the markups are vectorized; the deliverable is assembled.
5. Read-out with the facility manager and (if applicable) the AHJ. Findings are discussed, priorities ranked, follow-up scheduled.

Deliverable

• Inventory PDF

  Numbered fixture list, location, hazard class, protection required vs installed, recommended action, estimated cost. Roughly 1 page per 8 fixtures.

• Marked-up plan drawings

  Each fixture located on its floor plan with the corresponding number. PDF.

• Submission package to AHJ (optional)

  If you want us to file the survey with MWW as a supplement to your master list, we will. The MWW Cross-Connection Control Section prefers having the document on file.

Example findings (anonymized)

#	Fixture	Hazard	Installed	Required	Action
1.1	Janitor sink (B1, rm 014)	Mod	None	SVB	Install SVB · $920
1.2	Lab sink (1F, rm 117)	High	None	SVB + air-gap	Install + retrain · $1,160
1.3	Soda carbonator (1F kitchen)	High	DC 3/4″	RP 3/4″	Replace · $2,200
1.4	Cooling tower makeup (rooftop)	High	None	RP 1.5″	Install · $3,800
1.5	Containment at meter (B1)	—	RP 2″ (1996, Watts 909)	Same	OK · 2026 test due Jun 30

References