Salinity of water

Salinity is essentially how much dissolved salt is present in water. It’s a measure of the total amount of minerals—mainly sodium (Na⁺) and chloride (Cl⁻)—but also includes other ions like magnesium, calcium, potassium, sulfate, and bicarbonate.

Here’s a clear, practical explanation tailored to understanding borewell water issues such as in Dumai:

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1. What is salinity?

Salinity refers to the concentration of dissolved salts in water.
It affects how “fresh”, “brackish”, or “salty” the water is.

Common units of measurement

• TDS (Total Dissolved Solids) – mg/L or ppm

• EC (Electrical Conductivity) – µS/cm

• Salinity (ppt or ‰) – parts per thousand

TDS and EC are most commonly used for groundwater testing.

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2. Categories of water salinity

Type of Water	TDS (mg/L / ppm)	Taste & Use
Freshwater	< 1,000	Good for drinking
Slightly salty (brackish)	1,000–3,000	Often not suitable for drinking
Moderately salty	3,000–10,000	Not drinkable
Highly saline	> 10,000	Seawater level

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3. Why groundwater becomes salty

Especially in coastal areas like Dumai, salinity problems are very common. Causes include:

(A) Seawater Intrusion

The biggest reason.
When wells are over-pumped, freshwater pressure drops and seawater moves into the aquifer, increasing salt levels.

(B) Evaporation and Tidal Influence

In flat coastal zones, mineral-rich groundwater can rise during high tide and leave salts behind.

(C) Old trapped seawater

Some aquifers naturally contain ancient seawater from thousands of years ago.

(D) Industrial/land contamination

Certain industries release brine or salty wastewater, raising TDS in nearby wells.

(E) Natural geological minerals

Some rocks dissolve slowly and release salts into groundwater.

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4. Impacts of high salinity on household life

Health impacts

• Not ideal for drinking

• Can increase sodium intake — not good for people with hypertension

• Bad for infants and pregnant women

• Water tastes metallic or salty

Household damage

• Corrosion of pipes and fittings

• White crust on kettles, heaters, toilets

• Soap won’t lather properly

• Plants and grass may die from salt stress

Effect on appliances

• RO filters get blocked faster

• Washing machines and water heaters corrode quicker

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5. How to detect salinity easily

Simple signs

• Water tastes salty

• Skin feels sticky after shower

• Soap doesn’t foam

• White deposits on faucets

Better: test EC or TDS

A cheap TDS meter (RM 20–40 / IDR 60k–120k) can instantly show if water is brackish.

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6. How to remove salinity

This part is important:

👉 Boiling, chlorine, UV, or ceramic filters cannot remove salt.
👉 The only household method to reduce salinity significantly is Reverse Osmosis (RO).

Options

1. RO filter (for drinking only)

   • Removes 95–99% salts

   • Produces small amount of pure water

   • Best for homes in coastal/seawater intrusion areas

2. Purchase treated / PDAM water for drinking

3. For entire house system

   • Very expensive (industrial RO or large-scale treatment)

   • Usually not practical for households

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7. Summary

• Salinity = amount of dissolved salts in water

• High in many coastal borewells including Dumai

• Caused by seawater intrusion, geology, or over-pumping

• Affects taste, health, plumbing, and everyday use

• Can’t be removed by boiling or chlorine

• RO filtration is the only effective household solution