Make Up Water In Cooling Tower _verified_ May 2026

| Loss Type | Description | Typical % of Circulation | |-----------|-------------|--------------------------| | | The primary cooling mechanism. Pure water vapor escapes. | 1–2% per 10°F (5.5°C) range | | Drift (Windage) | Small droplets carried out by exhaust air. | 0.001–0.2% (modern drift eliminators) | | Blowdown (Draw-off) | Intentional bleed to control dissolved solids. | Varies (0.5–5% of circulation) | | Leaks/Overflow | System losses from seals, basins, or splashing. | Minimal if maintained |

Assume 0.01% of circulation for well-maintained towers: D = 1000 × 0.0001 = 0.1 gpm make up water in cooling tower

| Parameter | Ideal Range | Why it matters | |-----------|-------------|----------------| | | 50–400 ppm (as CaCO₃) | Scale formation at high pH/temp | | Total alkalinity | < 400 ppm (as CaCO₃) | Decomposes to CO₂, lowers pH | | pH | 6.5–8.5 | Corrosion <6.5, scaling >8.5 | | Chlorides | < 500 ppm | Pitting corrosion (especially stainless steel) | | Silica | < 150 ppm | Hard, glass-like scale | | TSS | < 50 ppm | Fouling, sediment | | Iron | < 0.5 ppm | Staining, fouling | | Bacteria | No legionella or E. coli | Health risk (Legionnaires' disease) | | Loss Type | Description | Typical %

1. What is Make-Up Water? Make-up water is fresh water added to a cooling tower system to compensate for total water losses. Without it, the system would run dry, lose efficiency, and suffer severe damage. 2. Why is Make-Up Water Needed? Water leaves a cooling tower system in three primary ways: coli | Health risk (Legionnaires' disease) | 1