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View of an open underground water well with a blue pressure tank and connected piping inside a concrete lining. The circular top edge and surrounding earth are visible, reminiscent of the meticulous work often seen by a skilled drainage contractor.

Percolation Test in Andover

Understanding the importance of a professionally conducted percolation test is critical for any property owner planning drainage installations in Brockenhurst, Ringwood, Andover, Beaulieu, or the wider New Forest area. Whether designing a new septic system, planning a drainage field, or developing land for agricultural or construction use, this test ensures full compliance with drainage regulations and environmental protection laws. When performed by Smart Drainz’ expert technicians, a percolation test will assess the soil’s capacity to absorb water, ensuring long-term functionality and environmental safety for systems relying on sub-surface wastewater dispersal.

What is a Percolation Test?

A percolation test, commonly referred to as a “perc test,” is a field-based assessment that evaluates the infiltration rate of soil. This information is critical when designing septic tank drainage fields, infiltration basins, and other subsurface water dispersal systems. For any drainage installations involving foul water discharge being undertaken in or around Brockenhurst, Ringwood, Beaulieu, Andover or the New Forest, this test is a legal and engineering prerequisite.

A typical test involves:

  • Excavation of at least two test holes, each 300mm x 300mm wide and at least 300mm deep, in the proposed drainage field area.
  • Soil saturation, ensuring the hole mimics long-term wet weather conditions.
  • Timed water infiltration measurement to calculate the percolation rate.

The test must be conducted when the groundwater table is neither seasonally high nor artificially low to yield reliable results.

Key factors that influence the test outcome include:

  • Soil Type: Clay-heavy soils generally drain poorly, while sandy soils exhibit faster infiltration.
  • Soil Structure & Texture: Root channels, granular cohesion, and particle sizes all affect drainage.
  • Groundwater Depth: High water tables can restrict the effectiveness of a proposed drainage field.
A person wearing blue gloves and boots is holding a green hose, operating near an open septic tank in a grassy area, perhaps addressing blocked drains. A removed concrete lid with a handle lies nearby, revealing the dug-up ground beneath.
A construction site with two rectangular excavations in the ground. One pit reveals an orange pipe amidst muddy soil, possibly needing a CCTV survey, while the other shows a green pipe, surrounded by bricks and soil. There's a section of brick paving at the top.

When to Schedule a Percolation Test

Smart Drainz recommends carrying out a percolation test during the early stages of planning for any of the following:

  • New drainage installations
  • Septic tank or sewage treatment plant upgrades
  • Planning application submissions requiring evidence of ground suitability
  • Replacement of failing or non-compliant systems

Regulatory guidance stipulates that the drainage field must be:

  • At least 10 metres from any watercourse
  • A minimum of 15 metres from any building
  • At least 50 metres away from any potable water supply

Early testing prevents costly redesigns and ensures that the proposed system meets Environment Agency standards for compliance.

Percolation Test FAQ

Why do I need more than one test hole?

Two or more holes provide a representative sample of soil performance across the entire drainage field area. This ensures the system is designed using reliable data.

Can a percolation test fail?

Yes. Clay-heavy or waterlogged soils often fail. If this occurs, our drain engineers will advise on suitable alternative solutions, such as raised beds or specialist filtration units.

What if I skip the percolation test?

Omitting the test can result in a failed system, environmental harm, and non-compliance with planning and drainage regulations. It could also delay approval or lead to legal penalties.

Do you conduct tests in protected zones like the New Forest?

Absolutely. Our team has extensive experience working in regulated landscapes such as the New Forest, Beaulieu, Ringwood, Andover, Brockenhurst and surrounding locations. We always operate with environmental sensitivity and regulatory precision.

Contact Smart Drainz

Need a professional percolation test conducted in Brockenhurst, Ringwood, Andover, Beaulieu, or the New Forest? Whether you’re planning new drainage installations, upgrading a septic system, or verifying compliance with drainage regulations, Smart Drainz offers expert assessment and tailored solutions. Get in touch with our certified drain engineers on 07950 753233 to book your site survey today.