Services Cooling Tower Optimization

Service — Cooling Tower Optimization

Cooling Tower Water Waste:
The $200K Hidden Cost
No One Monitors.

Cooling towers in full-service hotels and office buildings account for 25–40% of total water consumption. Most are operating at bleed rates set at conservative manufacturer defaults — wasting 15–30% of make-up water above the optimum for local water chemistry. WST audits, recalibrates, and monitors.

Schedule Cooling Tower Assessment How It Works ↓

25–40%

Of total building water consumption — cooling towers in full-service hotel/office

15–30%

Average make-up water waste from default bleed rate settings

$15–40K

Annual savings per asset from bleed rate recalibration alone

Zero

Capital investment required — bleed rate adjustment is operational, not capital

The Problem

Cooling towers are factory-set to waste water.
Almost no one changes the defaults.

Cooling tower bleed rates are set by manufacturers to protect equipment under worst-case water chemistry conditions. For most US commercial properties, local water quality is far better than the worst case — meaning the default bleed rate is wasting water that doesn't need to be expelled. The optimum bleed rate depends on local water chemistry, tower design, and cooling load. Without a water chemistry analysis and site-specific calculation, the default is always over-conservative.

Bleed rate set to manufacturer default

Manufacturer default bleed rates are calibrated for water chemistry with high dissolved solids — the worst-case scenario for scale and corrosion. Most US municipal water supplies are significantly better than this threshold. Operating at the default bleed rate in a low-TDS water supply area wastes water protecting against a risk that doesn't exist at the local level.

Sewer charges on water that never enters sewer

Cooling tower make-up water evaporates — it never enters the municipal sewer. Most utilities charge sewer fees on total water consumption unless the property files a sub-meter or non-return exemption. Hotels and office buildings paying sewer fees on cooling tower make-up water are paying for a service they're not receiving, often for years before the error is identified.

Make-up water volume not sub-metered

Without a dedicated sub-meter on the cooling tower make-up line, total consumption cannot be split between tower use and other building systems. This prevents sewer exemption filing, makes it impossible to identify anomalous tower consumption, and leaves the property without the data required for GRESB MR3 target documentation on the most significant water-consuming system in the building.

WST Methodology

Four steps from baseline
to optimised tower.

WST's cooling tower optimisation programme is not a one-time adjustment. It establishes the data infrastructure, calculates the optimal operating parameters, implements the changes, and monitors performance on an ongoing basis.

Water Chemistry Analysis

Local municipal water quality report reviewed against tower specifications. Cycles of concentration calculated for the specific water chemistry. Optimum bleed rate determined for the tower's cooling load and local TDS levels — replacing the manufacturer default with a site-specific target.

Make-Up Volume Measurement & Sewer Exemption Filing

Sub-metering installed on make-up water supply if not already present. Historical make-up volumes estimated from current consumption data. Sewer exemption application prepared and filed with the municipal utility for all eligible non-returned water volume — tower evaporation, drift, and blowdown.

Bleed Rate Recalibration & Controller Adjustment

Tower controller programmed to the site-specific optimal bleed rate. Conductivity set-point adjusted to maintain cycles of concentration at the calculated optimum. Drift eliminator condition assessed. Any mechanical issues affecting bleed rate control identified and documented for maintenance scheduling.

IoT Monitoring & Continuous Verification

Smart sensor on make-up line tracks consumption against the new optimised baseline. Anomalies — consumption above the expected range for the current cooling load — trigger cost-quantified alerts before they become billing events. Monthly performance reports confirm savings against pre-optimisation baseline for investment committee and GRESB documentation.

Cooling Tower Optimisation — Typical Outcomes

Make-up water reduction15–30%

Annual cost saving (per tower)$15–40K

Sewer exemption recovery (where applicable)$18–45K/yr

Retroactive sewer credit recoveryUp to 5 years

Implementation timeline1–3 days on-site

Capital investment requiredZero (operational adjustment)

Payback periodFirst billing cycle

Request Cooling Tower Assessment

What WST Monitors Post-Optimisation

Make-up water flow rate

Continuous flow measurement vs. cooling load ratio — any deviation from expected range triggers an alert

Bleed / blowdown volume

Actual bleed rate vs. calculated optimum — drift indicates controller fault or water chemistry change

Overnight consumption

Tower make-up at 3am should be zero or minimal — any sustained overnight flow indicates a fault or valve leak

Sewer exemption compliance

Sub-metered make-up volumes confirmed for utility exemption filing — ensures exemption credits continue uninterrupted

Applications

Property types where cooling tower
optimisation delivers the highest returns.

Full-Service Hotels & Hotel REITs

Centralised chilled water plant serving guest rooms, restaurants, event space, and back-of-house. Cooling towers typically running year-round in Florida and Southeast US climates. Sewer exemption on pool make-up frequently applicable alongside tower optimisation.

Class A Office Buildings

Cooling towers serving centralised HVAC systems in multi-tenant office buildings. Multiple towers on large footprint properties create compounding savings opportunity. Tenant sub-metering often provides the monitoring infrastructure for GRESB MR3 credit.

Mixed-Use & Institutional Portfolios

Multi-asset portfolios with varying building ages and cooling system vintages. Oldest equipment typically carries the highest deviation from optimal bleed rates. Portfolio-level optimisation delivers compounding aggregate savings across all assets.

Manufacturing & Industrial Facilities

Process cooling towers with high and continuous loads. Water quality variation and seasonal make-up demand require more dynamic bleed rate management. WST's chemical treatment coordination ensures optimised bleed rates remain compatible with corrosion and scale control targets.

Healthcare & Medical Campuses

Year-round cooling demand with regulatory compliance requirements. WST's documentation framework is structured to satisfy both operational efficiency targets and the risk quantification required for healthcare facility water management compliance programmes.

Portfolios Preparing for GRESB Submission

Cooling tower optimisation generates the verified baseline consumption data, monitored targets, and financial risk quantification required for WT1 coverage, MR3 evidence, and RA4 documentation — three indicators addressed by one programme.

GRESB Connection

Cooling tower optimisation addresses
three GRESB water indicators.

A cooling tower that has been sub-metered, optimised, and placed on continuous monitoring simultaneously satisfies the evidence requirements for WT1, MR3, and RA4 — the three water indicators that collectively account for ~7.67 points in the GRESB scoring model.

✓WT1 Data Coverage: Sub-metered make-up volume provides verified consumption data for the property's most significant water system — critical for WT1 coverage calculation.

✓MR3 Monitoring & Targets: IoT monitoring generates the continuous consumption record required for MR3. Optimised bleed rate becomes the documented target against which monitoring performance is measured.

✓RA4 Risk Assessment: Cost-quantified anomaly alerts (excess make-up flow, overnight consumption) constitute the financially-expressed water risk evidence RA4 requires at the asset level.

✓Sewer Exemption Documentation: Sub-metered make-up volumes provide the evidence basis for ongoing sewer exemption filing — eliminating recurring overcharges while creating GRESB-usable consumption records.

28%

Cooling tower make-up reduction — Miami full-service hotel, 2024

$38K

Annual sewer exemption credit recovered — same property

Day 1

Savings begin — bleed rate adjustment implemented during site visit

3 days

Typical on-site time for assessment and full optimisation

"The cooling tower adjustment took half a day. The sewer exemption filing took a week. The combined saving was $38,000 a year — and we'd been leaving it on the table for three years."

Engineering Director · Full-Service Hotel · Miami, FL

Common Questions

Cooling tower optimisation —
what to expect.

Does cooling tower optimisation require shutting the system down?

No. Bleed rate recalibration is performed on operating equipment — the controller adjustment requires the tower to be running, not shut down. WST completes the optimisation process during normal operations, typically within a single site visit. Sub-meter installation on make-up lines may require a brief valve isolation, which is coordinated with the engineering team to minimise any operational impact.

What is a sewer exemption and does my property qualify?

A sewer exemption (also called a non-return water credit or sewer discharge adjustment) is a billing adjustment available in most US municipalities for water that doesn't enter the sewer system. Cooling tower evaporation, pool make-up water, and irrigation water all qualify. To claim the exemption, properties must typically install a sub-meter on the non-return supply and file an application with the utility. WST handles the sub-meter specification, the application preparation, and the filing. Historical exemptions can typically be recovered for 2–5 years depending on the utility and jurisdiction.

How does WST calculate the optimum bleed rate?

The optimum bleed rate (expressed as cycles of concentration) is determined by the Langelier Saturation Index for the local water supply — a calculation that balances scale prevention against water waste. WST obtains the current municipal water quality report, cross-references against the tower's design specifications and current cooling load, and calculates the highest safe cycles of concentration for the local water chemistry. This is typically 1.5–2x higher than the manufacturer default, translating directly to a 30–50% reduction in bleed volume for the same cooling output.

Will optimising the bleed rate affect water treatment chemical costs?

Higher cycles of concentration require more active chemical treatment to maintain corrosion and scale control. WST's optimisation programme includes a review of the current chemical treatment programme and, where necessary, a recommendation for treatment adjustment to match the new operating parameters. In most cases, the reduction in water and sewer costs significantly exceeds any increase in chemical treatment costs — the net saving remains strongly positive. WST documents the full programme economics including chemical treatment in the client findings report.

Related Services

Services that complement
cooling tower optimisation.

Smart Water Monitoring

IoT monitoring on make-up lines post-optimisation

Verify savings and catch anomalies in real time →

Water Efficiency Audits

Full building water audit including all systems

Cooling tower plus billing validation and fixtures →

ESG & GRESB Strategy

Translate tower data into GRESB submission evidence

WT1, MR3, and RA4 documentation →

How much is your cooling tower
wasting right now?

A WST cooling tower assessment identifies the specific make-up water waste at your property, calculates the optimum bleed rate, and documents the annual saving — typically delivered within 48 hours of on-site visit.

Schedule Assessment

Cooling Tower Water Waste:The $200K Hidden CostNo One Monitors.

Cooling towers are factory-set to waste water.Almost no one changes the defaults.

Four steps from baselineto optimised tower.

Property types where cooling toweroptimisation delivers the highest returns.

Cooling tower optimisation addressesthree GRESB water indicators.

Cooling tower optimisation —what to expect.