Drinking well water (air sumur) – common problems and what you can do about them
Many households in Indonesia use their own well – either as their main or supplementary source of water. Well water may look clear but can still be contaminated. Here you can find out what problems are common, why a laboratory test is the first step, and what role a filtration system can play.
Summary
- Common problems with well water: bacteria (e.g. from a nearby septic tank), iron and manganese, limescale and a smell of rotten eggs.
- Only a laboratory analysis can determine whether well water is safe to drink – appearance, smell and a TDS meter are not sufficient.
- Reverse osmosis also works with well water – depending on the water, pre-treatment such as a sediment or iron/manganese filter may be required before the system.
1. Typical problems with well water
| Problem | How to recognise it | Cause |
|---|---|---|
| Germs (e.g. E. coli) | Usually no signs at all – the water may be clear | Septic tank too close to the well; surface water seeps in |
| Iron | Yellowish water, brown stains on tiles and laundry, metallic taste | iron-rich soil |
| Manganese | black or dark deposits | manganese-rich soil |
| Limescale (hardness) | white limescale deposits in the kettle | calcareous subsoil |
| Hydrogen sulphide | Smell of rotten eggs | Decomposition of organic matter in the soil |
Germs in particular are tricky: you can’t see, smell or taste them. Boiling kills germs, but it doesn’t remove iron, limescale or chemical substances.
2. First step: Have the water tested in a laboratory
A TDS meter only detects dissolved substances, not bacteria (more on this in the article ‘What is TDS?’). For well water, it’s worth having a laboratory analysis carried out that covers at least bacteria (E. coli, coliform bacteria), iron, manganese, hardness, pH and nitrate. Regional health laboratories, for example, offer such tests.
Do you already have a laboratory report? Upload it to ‘Test your water’ on our website. We’ll analyse the results and explain them to you in simple terms.
3. How well water is treated
What’s required depends on the results. Often, it’s a combination of:
- sediment filters to remove sand and turbidity,
- iron and manganese removal for high iron or manganese levels,
- disinfection (e.g. UV) for bacterial contamination,
- and, for drinking water, a reverse osmosis system that removes dissolved substances.
Important: A reverse osmosis (RO) system should not be operated without protection when using heavily contaminated raw water. High iron or manganese levels and sand quickly clog the pre-filters and membrane. Therefore, depending on the analysis, pre-treatment is required upstream of the system when using well water – after which the reverse osmosis system delivers clean drinking water.
Example: a villa with a well. The well water first passes through the pre-treatment stage (e.g. a sediment filter or water softener) into a large raw water tank. From there, a pressure pump supplies the TLW 7 with a pressure of at least 1 bar. Downstream of the system, a T-piece divides the filtered water: one pipe carries drinking water directly to the kitchen, whilst the other fills a purified water tank, which supplies the bathrooms and showers.
4. Well and septic tank: Check the distance
If the septic tank is too close to the well, germs can enter the groundwater. Check the distance on your property and, if possible, on your neighbours’ properties too. After heavy rain or flooding, you should treat well water with particular care and, if in doubt, have it retested.
Conclusion
When it comes to well water, the rule is: test first, then filter. Laboratory analysis will show what pre-treatment is required. Afterwards, a reverse osmosis system ensures clean drinking water straight from the tap. Send us your laboratory report via ‘Test Your Water’ or via WhatsApp – we’ll tell you what’s best for your water.