Using raw hydrochloric acid (HCl) to clean a groundwater well

Using raw hydrochloric acid (HCl) to clean a groundwater well is risky for several reasons — and our contractors photo of the destroyed poly impeller is a textbook example of the damage it can cause.

Here’s a clear breakdown of the problems:

1. Aggressive Material Attack

• Polymer and plastic parts (impellers, pump housings, seals) can soften, crack, or completely dissolve after repeated HCl exposure.

• Metals such as mild steel, galvanised steel, and even some grades of stainless steel can pit and corrode quickly.

• Rubber seals, o-rings, and gaskets often lose elasticity or disintegrate.

  
  

2. No Selectivity – Removes Good with the Bad

• HCl attacks not only the scale or iron oxide you want to remove but also the surrounding well screen, casing, and pump fittings.

• This can enlarge screen slots, weaken joints, and shorten the life of the infrastructure.

3. Violent Reaction with Iron-Related Bacteria (IRB) and Carbonates

• Raw acid reacts rapidly, generating heat, hydrogen gas, and suspended solids.

• The fast reaction creates turbulence that can stir up deep sediment, which then blocks pump intakes or damages moving parts.

4. Safety Hazards

• Concentrated HCl gives off highly corrosive fumes that can burn eyes, skin, and lungs.

• Hydrogen gas generation poses an explosion risk in confined spaces.

• Risk of severe chemical burns during handling and mixing.

5. Environmental Risks

• Any uncontrolled discharge of acid or acidic flush water can kill aquatic life and contaminate soil.

• Neutralisation after cleaning is critical, but many operators underestimate the volume of neutraliser needed.

6. Short-Term Gain, Long-Term Pain

• HCl can give an instant improvement in water flow, but the damage to materials means pumps, impellers, and well screens often fail much sooner.

• Repeated treatments compound the damage — your destroyed impeller is proof.

Better alternatives:Specialised well rehabilitation chemicals (like BoreSaver Ultra C) are designed to target iron-related bacteria and mineral fouling without attacking pump components or casing materials. They’re safer to handle, biodegradable, and don’t produce hazardous fumes.