3.3 Enhanced Water Quality (W04), Drinking Water Quality Management (W05) & Drinking Water Promotion (W06)
Key Takeaways
- W04 Enhanced Water Quality is a 1-point optimization setting aesthetic thresholds for taste, odor and appearance, including TDS 500, chloride 250, sulfate 250, sodium 270, copper 1, iron 0.3 and free chlorine 1.25 mg/L.
- W05 Part 1 Option 1 requires first-time projects to pre-test 11 water parameters at least one month before Performance Verification, with treatment devices removed, at prescribed dispenser locations.
- W05 pre-test sampling locations are the dispenser closest to the incoming pipe, plus for projects over two floors one on the highest floor and the farthest accessible one, plus one additional dispenser per 10 floors for projects of 12 or more floors.
- W05 Part 1 Option 2 requires quarterly testing of piped drinking water against eight thresholds, with remediation and re-testing within a month of any exceedance.
- W06 Drinking Water Promotion requires at least one dispenser per floor within a 100 ft (30 m) walk distance of all regularly occupied floor area and in all dining areas, with new fountains designed for bottle refilling and daily cleaning of touch points.
3.3 Enhanced Water Quality (W04), Drinking Water Quality Management (W05) & Drinking Water Promotion (W06)
Core Exam Takeaway: These three features are the most commonly mis-numbered in the Water concept. W04 = Enhanced Water Quality (aesthetic thresholds, 1 pt). W05 = Drinking Water Quality Management (pre-test + quarterly monitoring + transparency, 3 pt). W06 = Drinking Water Promotion (dispenser access and maintenance, 1 pt). If you have "W04 Drinking Water Promotion" in your notes, correct it now — that is W06.
Why aesthetics is a health strategy
Water that is safe but tastes of chlorine, metal or sulfide loses to soda. Mild hypohydration — a fluid loss of just 1–2% of body mass — measurably impairs cognitive processing speed, short-term working memory, executive decision-making and vigilance while increasing perceived fatigue and tension. WELL therefore pays separately for water that is palatable (W04), demonstrably monitored and disclosed (W05), and physically within reach (W06).
Feature W04: Enhanced Water Quality — Optimization (1 pt / WELL Core 2 pt)
Intent: provide access to drinking water without unpleasant taste, odor and appearance.
W04 Part 1 — Meet Thresholds for Drinking Water Taste
Water delivered to the project for human consumption meets all twelve thresholds:
| Parameter | W04 threshold | Sensory effect if exceeded |
|---|---|---|
| Aluminum | ≤ 0.2 mg/L | Discoloration, turbidity |
| Chloride | ≤ 250 mg/L | Salty taste, corrosivity |
| Copper | ≤ 1 mg/L | Metallic taste, blue-green staining |
| Manganese | ≤ 0.05 mg/L | Black staining, bitter taste |
| Iron | ≤ 0.3 mg/L | Rusty color, metallic taste |
| Silver | ≤ 0.1 mg/L | Discoloration |
| Sodium | ≤ 270 mg/L | Salty taste |
| Sulfate | ≤ 250 mg/L | Bitter taste, laxative effect |
| Sulfide | ≤ 0.05 mg/L | Rotten-egg odor |
| Zinc | ≤ 5 mg/L | Astringent taste, milky appearance |
| Total Dissolved Solids (TDS) | ≤ 500 mg/L | Flat or briny taste, scaling |
| Free chlorine | ≤ 1.25 mg/L | Swimming-pool taste and odor |
[!IMPORTANT] Copper appears in both W02 and W04 with different numbers. W02's health limit is 2 mg/L; W04's aesthetic limit is 1 mg/L, because people taste copper long before it harms them. The same logic explains why free chlorine is 4 mg/L in W02 but 1.25 mg/L in W04. When an exam item gives you a copper or chlorine value, check which feature it is asking about.
[!WARNING] Sodium is 270 mg/L in W04, not 20 mg/L. The 20 mg/L figure is a clinical low-sodium-diet guideline that circulates widely in study materials; it is not WELL's threshold.
WELL Core guidance: whole building, sampled from non-leased spaces with the same treatment-system confirmation or tenant allowance provisions as W02.
Feature W05: Drinking Water Quality Management — Optimization (3 pt / WELL Core 3 pt)
Intent: maintain and display consistent high quality of drinking water. This is the Water concept's highest-value optimization, and its mechanics are richly testable.
W05 Part 1 — Assess and Maintain Drinking Water Quality (2 pt)
Option 1: Water quality pre-test. For first-time registered projects:
-
(a) Pre-test water at least one month before Performance Verification for eleven parameters: turbidity, coliforms, pH, TDS, total chlorine, residual (free) chlorine, arsenic, lead, copper, nitrate, benzene.
-
(b) Sample at these locations, with filters or other water treatment devices removed if present:
- The water dispenser closest to the pipe that delivers water into the project.
- For projects with more than two floors: a dispenser on the highest floor, and the dispenser located farthest from location (1) to which the project has access.
- For projects of 12 or more floors: one additional dispenser for every 10 floors.
Projects under recertification do not need to pre-test water to achieve this Part.
Option 2: Water quality monitoring.
- (a) Piped water is delivered to drinking water dispensers.
- (b) Water is tested quarterly at drinking water dispensers against these thresholds; if any sample exceeds them, remediation and re-testing occur within a month:
| Parameter | W05 quarterly threshold | Frequency relief |
|---|---|---|
| Turbidity | ≤ 1.0 NTU, FTU or FNU | — |
| pH | between 6.5 and 9.0 (between 5.5 and 9 if point-of-use reverse osmosis is installed) | — |
| TDS | ≤ 500 mg/L | — |
| Total chlorine | ≤ 5 mg/L | — |
| Residual (free) chlorine | ≤ 5 mg/L | — |
| Total coliforms | not detected in a 100 ml sample; testing required only if residual chlorine is not detected | — |
| Lead | ≤ 10 µg/L | reduce to once per year after results below detection limits in two consecutive samples |
| Copper | ≤ 2 mg/L | reduce to twice a year if below 0.1 mg/L in two consecutive samples; testing no longer required after four consecutive samples below 0.1 mg/L |
- (c) Sampling points comply with the Performance Verification Guidebook. (d) All results are submitted annually through the WELL digital platform.
+-----------------------------------------------------------------------------+
| W05 PART 1 OPTION 2: SAMPLING-FREQUENCY RELIEF LADDER |
| |
| LEAD |
| Quarterly --> 2 consecutive samples BELOW DETECTION --> Annual |
| |
| COPPER |
| Quarterly --> 2 consecutive samples < 0.1 mg/L --> Twice a year |
| --> 4 consecutive samples < 0.1 mg/L --> Testing NOT required |
| |
| ANY EXCEEDANCE OF A W05 THRESHOLD |
| --> Remediation AND re-testing within ONE MONTH |
+-----------------------------------------------------------------------------+
[!TIP] The pH window is the only two-sided range in the Water concept: 6.5–9.0, widening at the bottom to 5.5 where point-of-use reverse osmosis is installed — because RO strips buffering minerals and legitimately produces slightly acidic water.
W05 Part 2 — Promote Drinking Water Transparency (1 pt)
The following is prominently displayed near sources of drinking water, or on a website available to occupants:
- (a) Water quality results from the most recent sampling, including the date of testing and compliance with WELL thresholds.
- (b) If filters or other treatment units are in use: information about the treatment technologies and the most recent date of device maintenance and/or filter cartridge replacement.
WELL Core guidance: non-leased spaces; displays in tenant-accessible areas or otherwise made available to tenants.
Feature W06: Drinking Water Promotion — Optimization (1 pt / WELL Core 1 pt)
Intent: promote proper hydration through consumption of drinking water over less healthy alternatives, by promoting access to drinking water of verified quality.
W06 Part 1 — Ensure Drinking Water Access
For all spaces except dwelling units.
Option 1: Dispenser availability — all three:
- (a) At least one drinking water dispenser — minimum one per floor — located within a 100 ft (30 m) walk distance of all regularly occupied floor area and in all dining areas.
- (b) Water delivered by the dispensers is directly piped through the building's water supply, or stored in containers designed for refilling.
- (c) All newly installed drinking water fountains are designed for water bottle-refilling.
Option 2: Dispenser maintenance — all drinking water dispensers have their mouthpieces/outlets, protective guards, aerators (if present), basins and touch points cleaned on a daily basis.
WELL Core guidance: whole building. For each 900 m² [10,000 ft²] of leased space, projects may provide one water supply and drainage point that can be connected to a drinking water dispenser — a Core-specific accommodation that lets a base building satisfy the feature without fitting out tenant kitchens.
[!TIP] W06's numbers to hold: 100 ft (30 m) walk distance, minimum one dispenser per floor, all dining areas, daily cleaning, and the WELL Core 900 m² / 10,000 ft² supply-and-drainage-point allowance. Note that (a) is a walk distance, so partitions, security doors and circulation routes count against you — not straight-line distance.
A project's drinking water contains 1.6 mg/L of free chlorine and 1.4 mg/L of copper. Which WELL v2 features does this water satisfy?
Under Feature W05 Part 1 Option 1, when must a first-time registered project conduct its water quality pre-test, and how must samples be taken?
A project monitoring under W05 Part 1 Option 2 records copper below 0.1 mg/L in four consecutive quarterly samples. What sampling obligation remains for copper?
Feature W06 Part 1 Option 1 requires drinking water dispensers to be located within what walk distance, and with what floor-level minimum?