Chapter 6 — WATER SUPPLY AND DISTRIBUTION
601.3 Identification of a Potable and Nonpotable Water System — 2025 California Plumbing Code
California Plumbing Code (Title 24, Part 5) · 2025 edition · updated 2026-10-19 · California
CBSC: official editions, supplements and errata
Italicized text is a California amendment to the model code, as printed in the official publication.
Cite as: 2025 California Plumbing Code (Title 24, Part 5) § 601.3 · Effective January 1, 2026 · Official source: Building Standards Commission
Water System. In buildings where potable water and nonpotable water systems are installed, each system shall be clearly identified in accordance with Section 601.3.1 through Section 601.3.5.
601.3.1 Potable Water. Green background with white lettering.
601.3.2 Color and Information. Each system shall be identified with a colored pipe or band and coded with paints, wraps, and materials compatible with the piping.
Except as required by Section 601.3.3, nonpotable water systems shall have a yellow background with black uppercase lettering, with the words “CAUTION: NONPOTABLE WATER, DO NOT DRINK.” Each nonpotable system shall be identified to designate the liquid being conveyed, and the direction of normal flow shall be clearly shown. The minimum size of the letters and length of the color field shall comply with Table 601.3.2.
[HCD 1 & HCD 2] An international symbol of a glass in a circle with a slash through it shall be provided sim- ilar to that shown in Figure 601 for all nonpotable water
systems.
FIGURE 601
INTERNATIONAL SYMBOL
The background color and required information shall be indicated every 20 feet (6096 mm) but not less than once per room, and shall be visible from the floor level.
601.3.3 Alternate Water Sources. Alternate water source systems shall have a purple (Pantone color No. 512, 522C, or equivalent) background with uppercase lettering and shall be field or factory marked as follows:
(1) Gray water systems shall be marked in accordance with this section with the words “CAUTION: NONPOTABLE GRAY WATER, DO NOT DRINK” in black letters.
(2) Reclaimed (recycled) water systems for outdoor applications shall be marked in accordance with this section with the words: “CAUTION: NONPOTABLE RECLAIMED (RECYCLED) WATER, DO NOT DRINK” in black letters.
(3) On-site treated water systems shall be marked in accordance with this section with the words: “CAU TION: ON-SITE TREATED NONPOTABLE WATER, DO NOT DRINK” in black letters.
(4) Rainwater catchment systems shall be marked in accordance with this section with the words: “CAU TION: NONPOTABLE RAINWATER, DO NOT DRINK” in black letters.
Exception: [DWR] For recycled water supply systems that are within or a part of a building, the provisions of Section 1505.7 shall apply.
TABLE 601.3.2
MINIMUM LENGTH OF COLOR FIELD AND SIZE OF LETTERS
| OUTSIDE DIAMETER OF PIPE OR COVERING (inches) |
MINIMUM LENGTH OF COLOR FIELD (inches) |
MINIMUM SIZE OF LETTERS (inches) |
|---|---|---|
1⁄2 to 11⁄4 |
8 | 1⁄2 |
11⁄2 to 2 |
8 | 3⁄4 |
21⁄2 to 6 |
12 | 11⁄4 |
8 to 10 |
24 | 21⁄2 |
Over 10 |
32 |
31⁄2 |
For SI units: 1 inch = 25.4 mm
601.3.4 Fixtures. Where vacuum breakers or backflow preventers are installed with fixtures listed in Chapter 17, identification of the discharge side shall be permitted to be omitted.
601.3.5 Outlets. Each outlet on the nonpotable water line that is used for special purposes shall be posted with black uppercase lettering as follows: “CAUTION: NONPOTABLE WATER, DO NOT DRINK.”
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