Is Your New Borehole Actually Safe to Drink From?

A newly drilled borehole must be flushed, disinfected and laboratory-tested before use as a drinking water source. Skipping these steps risks exposure to drilling fluid contaminants and geological minerals.

What Happens During Drilling That Affects Water Quality

Borehole drilling introduces several contamination risks that must be addressed before the water is safe to consume. Drilling equipment carries lubricants, hydraulic fluids and hydrocarbon residues. The drilling process can also mobilise geological materials, fluoride, arsenic, manganese and iron, that were previously bound in rock strata above the aquifer.

Additionally, the drilling process disrupts the natural groundwater flow around the borehole, often temporarily drawing in shallower, less-protected water from surface layers. This typically clears within days but must be confirmed by testing.

The Mandatory Commissioning Steps

Kenya Water Resources Authority (WRA) and KEBS KS 459 specify the following steps before a borehole is approved for domestic use:

Source: Kenya Water Resources Authority, Borehole Drilling Guidelines; KEWI Water Quality Lab Services.

Common Findings in New Borehole Water

• High iron and manganese: causes orange/brown staining and metallic taste, aesthetically unpleasant and at high levels poses health concerns.
• Elevated fluoride: common in Rift Valley geology; above 1.5 mg/L causes dental fluorosis; above 4 mg/L risks skeletal fluorosis.
• High total hardness: not a health risk but causes scale buildup and interferes with soap and appliances.
• Elevated TDS: a marker for dissolved mineral load; requires further testing to identify specific parameters.

Which Treatment Is Right for Your Borehole?

The correct treatment system depends on your laboratory results. Reverse osmosis is highly effective for reducing fluoride, nitrates, heavy metals, and overall TDS. Where iron levels are very high, a pre-treatment iron removal unit is recommended before the RO membrane to extend membrane life.

Q: My driller says the water looks clear so it must be safe, is that right?

A: Clarity alone is not an indicator of safety. Fluoride, nitrates and many bacteria produce no visible change in water appearance. Laboratory testing is the only reliable method.

Q: How long after drilling should I wait before using the borehole?

A: At minimum 72 hours after shock chlorination and flushing. Testing results must confirm safety before regular use begins.

Start your borehole right

iClear assesses your laboratory results and recommends the right treatment solution for your specific water chemistry. Find out more.