What is Borehole Casing?
Borehole casing is the pipe that lines your borehole, preventing the walls from collapsing and keeping surface contaminants from entering the groundwater. It's one of the most critical components of your borehole system—and one of the most expensive to repair if damaged.
At WaterLink Limited, a WRA licensed borehole drilling company with Class A status, we've repaired hundreds of damaged casings across Kenya. This guide explains everything you need to know about borehole casing repair, from identifying problems to choosing the right repair method.
Key Fact: Casing is the only barrier between your borehole water and surface contamination. A damaged casing can allow pollutants to enter your water supply—posing serious health risks.
Common Causes of Casing Damage
Understanding what causes casing damage helps you prevent problems and identify issues early:
Corrosion (Steel Casing)
Steel casing can corrode over time, especially in acidic groundwater or areas with high mineral content. Corrosion weakens the casing, leading to perforations, holes, and eventual collapse.
Brittle Failure (uPVC Casing)
uPVC casing can become brittle with age, UV exposure, or aggressive groundwater chemistry. Cracks can form, allowing sand and sediment to enter the borehole.
Geological Pressure
Unstable geological formations can exert pressure on the casing, causing it to collapse or deform. This is common in areas with loose soils or active fault lines.
Ground Movement
Earthquakes, soil settlement, or construction activities nearby can shift the ground and damage casing.
Poor Installation
Improper casing installation—incorrect depth, poor connections, or inadequate cementing—can lead to premature failure.
Age-Related Wear
All materials degrade over time. Steel casing typically lasts 30-50 years, uPVC 20-30 years, depending on conditions.
Accidental Damage
Damage can occur during pump replacement, drilling nearby, or other construction activities.
Warning: Casing damage is a serious problem. If left unaddressed, it can lead to borehole collapse, contamination, and loss of your entire water supply.
Signs Your Casing Needs Repair
Watch for these warning signs of casing damage:
- Sand or Sediment in Water: If your borehole water becomes sandy or murky, it's a sign the casing or screen is damaged.
- Decreased Water Yield: A sudden drop in flow rate often indicates casing collapse or screen blockage.
- Pump Damage or Failure: Sand entering the borehole can destroy your pump impellers.
- Visible Cracks or Damage at Wellhead: If you can see damage at the top of the borehole, there may be more below.
- Contamination or Water Quality Changes: If water quality suddenly changes, surface contamination may be entering through a damaged casing.
- Unusual Noises from the Borehole: Grinding, scraping, or rumbling sounds can indicate casing problems.
- Difficulty Removing or Installing the Pump: If the pump gets stuck, the casing may have collapsed or deformed.
Pro Tip: Regular CCTV inspections every 2-3 years can detect casing problems before they become emergencies. Early detection saves money and prevents failure.
CCTV Inspection: Diagnosing the Problem
A CCTV inspection is the most reliable way to diagnose casing problems. A high-definition camera is lowered into the borehole to visually inspect the casing condition.
What CCTV Reveals
- Collapsed sections: Areas where the casing has caved in
- Perforations and holes: Corrosion damage or cracks
- Casing joints: Whether joints are still intact
- Screen condition: Clogged or damaged screen openings
- Sediment buildup: Accumulation of sand or debris
- Water quality indications: Signs of contamination entering the borehole
When to Inspect
- Every 2-3 years: Recommended for all boreholes
- If you notice warning signs: Sediment, yield loss, or contamination
- Before pump replacement: To ensure the casing is safe for pump removal
- After any nearby construction: To check for damage
WaterLink Service: We provide professional CCTV inspection services with detailed video recordings and reports. Our technicians are trained to identify all types of casing problems.
Casing Repair Methods
Depending on the extent of the damage, different repair methods are available:
1. Liner Installation (Sleeve Repair)
A smaller diameter steel or uPVC liner is inserted inside the existing casing to bypass the damaged section. The liner is sealed at the top and bottom to prevent water from entering the damaged zone.
Best For: Collapsed sections, multiple perforations, or extensive corrosion.
✓ Most Common Method2. Patch Repair
A steel patch is placed over a small damaged section and secured in place. This is only suitable for localized damage.
Best For: Small holes or localized corrosion.
✓ Suitable for Minor Damage3. Cement Grouting
Cement grout is pumped behind the casing to seal cracks and prevent further damage. This method is often used in combination with other repairs.
Best For: Sealing cracks and preventing water leakage.
✓ Often Used with Other Methods4. Casing Removal and Replacement
In severe cases, the damaged casing must be removed and replaced. This is the most expensive and time-consuming option.
Best For: Completely collapsed or severely damaged casing.
✗ Most Expensive Option5. Complete Borehole Re-drilling
If repair is impossible or the casing is beyond salvage, a new borehole must be drilled at a different location.
Best For: Irreparable damage, multiple failed repairs.
✗ Last ResortImportant: Casing repairs are complex and require specialized equipment. Always use licensed professionals with experience in casing repair.
Casing Repair vs. Replacement
Deciding whether to repair or replace casing depends on several factors:
When Repair is the Best Option
- Localized damage (small hole or crack)
- Corrosion limited to a small section
- Casing is structurally sound overall
- Budget constraints
- Quick solution needed
When Replacement is Necessary
- Extensive corrosion throughout the casing
- Complete collapse or multiple collapses
- Casing diameter has significantly reduced
- Multiple repair attempts have failed
- Casing material has deteriorated beyond repair
Decision Factors
- Cost: Repairs are typically cheaper than replacement
- Time: Repairs are faster than complete replacement
- Longevity: Replacement provides a fresh start with longer lifespan
- Borehole value: Consider the age and overall value of your borehole
WaterLink Recommendation: We recommend a CCTV inspection and professional assessment to determine the best course of action. Most boreholes can be successfully repaired rather than replaced.
Cost of Casing Repair in Kenya
Casing repair costs vary based on depth, damage extent, and repair method. Here's what to expect:
| Repair Method | Typical Cost (KES) | Application |
|---|---|---|
| CCTV Inspection | 30,000 – 60,000 | Diagnostic |
| Patch Repair (Small) | 80,000 – 150,000 | Minor damage |
| Liner Installation (100-200m) | 250,000 – 450,000 | Moderate damage |
| Liner Installation (200-300m) | 400,000 – 600,000 | Severe damage |
| Complete Casing Replacement | 600,000 – 1,500,000+ | Extensive damage |
| New Borehole Drilling | 800,000 – 2,500,000 | Irreparable |
Note: Costs vary based on depth, accessibility, and specific conditions. WaterLink Limited provides a detailed quote after CCTV inspection.
ROI Insight: Spending KES 300,000 on a liner installation can protect your KES 1.5 million borehole investment and extend its life by 20-30 years.
How to Prevent Casing Damage
Prevention is always better than cure. Here's how to protect your casing:
- Choose the Right Material: Steel for deep, high-pressure aquifers; uPVC for shallow, low-pressure applications.
- Professional Installation: Always use licensed contractors for casing installation.
- Proper Cementing: Ensure casing is properly grouted to prevent corrosion and contamination.
- Regular Inspections: CCTV inspections every 2-3 years catch problems early.
- Maintain Proper Water Chemistry: Highly acidic or alkaline water can accelerate corrosion.
- Protect the Wellhead: Keep the wellhead sealed and protected from surface water.
- Avoid Over-pumping: Pumping at or below sustainable yield reduces stress on casing.
WaterLink Limited Casing Repair Services
WaterLink Limited offers comprehensive casing repair and rehabilitation services:
- CCTV Inspection: High-definition camera inspection with detailed reporting
- Liner Installation: Professional installation of steel or uPVC liners
- Patch Repair: Localized repair for minor damage
- Cement Grouting: Seal cracks and prevent further damage
- Complete Rehabilitation: Full borehole restoration services
- Emergency Response: 24/7 service for urgent casing failures
Need Casing Repair?
Contact WaterLink Limited for professional casing inspection and repair services.
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