Most of the worlds water sources are salty and due declining rainfall and drought conditions in many areas of Australia water quality has deteriorated. If your water source is anything other than town supply, it is worth monitoring quality at different times of the year. Testing for salt content is important as many ornamental plants show up salt damage quickly. It’s a good idea to test water now (November) and again in March every year. November is when winter rains have consolidated and flushed salts through the water system (in a non-drought affected area) and March testing will give the worst-case scenario. Depending on the area you live, and water availability will depend how much this reading will vary.
There are two main tests for salt content, either TDS (total dissolved solids) or EC (electrical conductivity. Both tests are totally acceptable for testing water quality for irrigation purposes.
The most common symptom of salt damage is burning around the margins of leaves.
In bad cases the plants will look like they have been severely sun burnt. The extent of this damage will also depend upon soil type, how much water from another source can be applied and the general health of the soil.