Construction and boiler feed water testing
Water used to mix concrete is checked for the impurities that attack reinforcement or interfere with setting — chloride, sulphate, organic matter and suspended solids. Boiler feed water is checked for the impurities that cause scale, corrosion and carryover. Both are suitability tests, not safety tests.
Water for concrete — IS 456 limits
Permissible limits for water used in mixing and curing plain and reinforced concrete under IS 456. Boiler feed water is assessed separately against the boiler manufacturer’s water chemistry specification.
| Parameter | Unit | Permissible limit | Why |
|---|---|---|---|
| pH value | — | Not less than 6 | Acidic water attacks cement paste |
| Organic matter | mg/L | 200 max | Interferes with setting and strength gain |
| Inorganic matter | mg/L | 3000 max | Total impurity load |
| Sulphates (as SO₃) | mg/L | 400 max | Sulphate attack on hardened concrete |
| Chlorides (as Cl) — reinforced concrete | mg/L | 500 max | Corrodes reinforcement steel |
| Chlorides (as Cl) — plain concrete | mg/L | 2000 max | No steel to protect, so relaxed |
| Suspended matter | mg/L | 2000 max | Affects water-cement ratio control |
What to send us
Test before the pour, not after
Site water is often drawn from a borewell sunk for the project, and in parts of coastal and South Bengal that water can carry chloride well above the reinforced-concrete limit. Chloride-driven corrosion does not show up for years, and by then the remedy is structural. A single test before the first major pour is the cheapest risk control on the job.
Questions about this test
Can I use borewell water for concrete?
Often yes, but it has to be tested first — particularly for chloride and sulphate. Proximity to the coast or to saline aquifers is the main risk factor, and it is not something you can judge by taste or appearance.
Is sea water ever acceptable?
Not for reinforced concrete. The chloride content is far above the IS 456 limit and will corrode reinforcement. It is sometimes tolerated in unreinforced mass concrete, but that is a design decision, not a testing one.
What do you test for boiler feed water?
Typically hardness, alkalinity, silica, chloride, dissolved oxygen indicators, TDS and conductivity — assessed against the pressure rating and the manufacturer’s specification, since a high-pressure boiler tolerates far less than a low-pressure one.