Industries Office Buildings
Industry — Office Buildings

Water Management for
Office Buildings & Class A Portfolios.

Multi-tenant office buildings carry billing complexity that most facilities teams never audit — cooling tower systems serving the whole building, tenant sub-metering mismatches, and HVAC make-up water that never appears in the sewer. WST identifies and recovers the overcharges while building the monitoring infrastructure for GRESB documentation.

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8–12%
Average billing overcharge found in office audits — before any operational improvement
25–40%
Of total office water consumption — cooling towers and HVAC make-up
$190K
Annual savings documented — 12-asset Class A office REIT, Mid-Atlantic
WT1
GRESB data coverage indicator most directly improved by systematic office auditing

The Office Challenge

Three water problems that Class A office
buildings carry silently.

Office buildings are not high-drama water users. The problems are structural and billing-related rather than operational — which is exactly why they persist for years without being addressed.

01
HVAC and cooling tower water not sub-metered — sewer charges applied to all of it

Centralised chilled water plants serving multi-tenant office buildings discharge cooling tower bleed water but the make-up volume feeding the towers is rarely sub-metered. Without a dedicated make-up meter, the property pays sewer charges on all water consumed — including the significant volume that evaporates through the cooling towers and never enters the sewer. In a 300,000 sq ft Class A building running chillers year-round, this can represent $20,000–$45,000 in annual sewer overcharges.

02
Tenant sub-metering mismatches generating billing disputes and unrecovered cost

Multi-tenant buildings with individual tenant sub-meters frequently develop discrepancies between the master utility meter and the sum of sub-meter readings — a gap that represents water consumed in common areas, mechanical rooms, and restrooms that isn't being allocated to any billing account. Over time, this gap compounds into unrecovered operating cost for the landlord. On a 20-tenant building, the common area water cost gap is often 8–15% of the total annual water bill.

03
No verified consumption data for GRESB WT1 — suppressing ESG scores for listed office REITs

Office REITs participating in GRESB frequently struggle with WT1 data coverage because utility bill collection across multi-tenant buildings with utility-paid leases is fragmented. Tenants who pay their own utility bills don't share data with the landlord. Without Ara AI's automated collection, the landlord cannot submit verified whole-building consumption data for WT1 — scoring lower than the building's actual water management performance warrants.

WST Approach

How WST addresses
the office building water profile.

Billing Audit — Rate, Sewer, & Sub-Meter Review
Master meter bills reviewed against municipal tariff schedules. Sewer charges cross-referenced against metered consumption by use type. Sub-meter totals reconciled against master meter — common area allocation gap quantified and documented for recovery.
Cooling Tower Optimisation & Make-Up Sub-Metering
Make-up water sub-meter installed where absent. Sewer exemption application prepared. Bleed rates recalibrated to site-specific optimum based on local water chemistry — reducing make-up volume by 15–25% while maintaining equipment protection.
IoT Monitoring — Cooling Loop, Common Area, & Irrigation
Real-time monitoring on cooling tower make-up, common area supply, roof drainage where irrigation is present, and any other non-returned water circuits. Anomaly alerts generated with cost-quantified impact within 48 hours of deviation onset.
Ara AI — WT1 Coverage for Multi-Tenant Portfolios
Ara acquires utility bills portfolio-wide including from tenant-paid accounts where accessible, producing GRESB WT1-compliant consumption data for the full building footprint. Whole-building consumption baselines documented for investment committee and ESG disclosure.

Typical Outcomes

Outcomes from WST office portfolio engagements.

Metric Outcome
Water cost reduction15–25%
Cooling tower savings (per asset)$15–40K/yr
Sewer exemption recovery$20–45K/yr
Sub-meter gap recovery8–15% of annual bill
GRESB WT1 coverage improvementPortfolio-wide closure
Payback period6–10 months

Shared-savings model: No upfront fees. WST's compensation tied to documented savings delivered.