Clear, cold borehole water can still be unsafe. Bacteria, fluoride and nitrate have no colour, smell or taste, so the only way to know is a laboratory test.
These are the seven tests every borehole owner in Kenya should know, what each one checks, and what to do if a result is out of range. For labs and prices, see our guide to borehole water testing in Kenya.
The 7 Essential Tests at a Glance
| Test | Guideline | Why it matters |
|---|---|---|
| 1. Bacteria (E. coli and coliforms) | None detected in 100 mL | Causes stomach illness; the most urgent result |
| 2. Fluoride | Up to 1.5 mg/L | Stains children’s teeth and, over many years, damages bones |
| 3. Nitrate | Up to 50 mg/L (as nitrate) | A risk for babies; a sign of septic or fertiliser pollution |
| 4. Iron and manganese | Iron about 0.3 mg/L for taste | Brown or black water, stains, metallic taste |
| 5. Salinity (TDS and chloride) | Chloride tastes salty above about 250 mg/L | Salty water tastes bad and harms crops and pipes |
| 6. Hardness | No health limit | Scale in kettles, pipes and tanks |
| 7. pH | 6.5 to 8.5 | Acidic water corrodes pipes; very alkaline water scales |
1. Bacteria
This is the first result to read. Any E. coli means the water has been in contact with human or animal waste and is not safe to drink until it is treated.
Common causes are a poorly sealed borehole, a pit latrine or septic tank nearby, or flooding. The usual fix is to shock chlorinate, find the source, then fit UV or chlorination.
2. Fluoride
High fluoride is common around Nairobi, Nakuru, Baringo and Kajiado. In Naivasha, a county study found fluoride of 2.15 to 6.5 mg/L in boreholes, well above the 1.5 mg/L guideline. See our Nakuru borehole guide.
Fluoride cannot be boiled away. For drinking water, use reverse osmosis or a defluoridation filter.
3. Nitrate
Nitrate comes from fertiliser, manure and septic systems. It is most dangerous for babies under six months, so never use high nitrate water for baby formula. Boiling does not remove it.
4. Iron and Manganese
Iron turns water brown and leaves orange stains. Manganese leaves black specks. Neither is usually a health emergency, but both ruin taste, laundry and fittings. Flushing the borehole and fitting an iron filter usually solves it. See signs your borehole needs flushing.
5. Salinity
Total dissolved solids (TDS) and chloride measure how salty the water is. Salt is a known risk along the coast and in parts of the north. Salty water tastes bad, corrodes pipes and can harm sensitive crops. Read how to predict salinity before drilling.
6. Hardness
Hard water is not a health risk, but it leaves white scale in kettles, tanks and pipes and makes soap less effective. A softener deals with it where needed.
7. pH
pH shows whether water is acidic or alkaline. Acidic water corrodes metal pipes and fittings, while very alkaline water can taste bitter and leave scale.
What Testing Costs
| Test | Typical price (KSh) | Source |
|---|---|---|
| Bacteriological analysis (WRA lab) | 2,000 | WRA |
| Full chemical analysis (WRA lab) | 5,000 | WRA |
| Basic private test | 5,000 to 8,000 | IGSL, 2025 |
| Comprehensive private test | 10,000 to 20,000 | IGSL, 2025 |
| Advanced, including heavy metals | 20,000 to 40,000 or more | IGSL, 2025 |
Every new Bonvic borehole includes a water quality analysis in the drilling price.
How Often to Test
- When the borehole is new, before anyone drinks the water
- Every year for homes
- Every six months for bacteria if the water is used for drinking
- After floods, pump or casing repairs, or any change in colour, taste or smell
See how often to test borehole water and what to do after drilling a borehole. For the health risks in more detail, read the hidden dangers in your borehole water.
Talk to Us Before You Drill
WhatsApp your town and county to 0727 666 444 or call 0797 000 555. We will tell you the expected depth and a cost range for your area. Office hours are Monday to Friday 8am to 5pm and Saturday 8am to 1pm.
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