Sampling and Inspection Wells

Sampling and Inspection Wells

Below is a clear explanation of the concepts sampling and inspection wells — what they are, how they are used, and why they are needed.

đŸ§Ș Sampling (in wastewater and stormwater systems)

Sampling means taking a water sample from a wastewater, stormwater, drainage, or treatment system to analyze:

  • contaminant levels

  • bacteria

  • pH

  • flow volume

  • treatment efficiency

  • infiltration or treatment performance

Sampling is commonly done for:

✔ Monitoring of on-site wastewater systems

Municipal authorities may require sampling to ensure the system is functioning correctly.

✔ Industrial discharge control

To verify that treatment stages such as sand filters, oil separators, or treatment plants are working properly.

✔ Stormwater quality control

When stormwater passes through sensitive or protected areas.

✔ Troubleshooting

Used when there are operational issues, odors, or suspected blockages.

Sampling is always taken from an accessible point, typically an inspection well.

🔍 Inspection Well (Control Well)

An inspection well, also called a control well, is a well installed in a wastewater or stormwater system that allows:

  • inspection

  • cleaning

  • camera inspection

  • sampling

  • flow measurement

  • troubleshooting

It functions as an access point to the pipeline.

🟩 Why Are Inspection Wells Used?

✔ 1. To monitor the condition of the system

You can identify:

  • water levels

  • frost damage

  • root intrusion

  • sludge buildup

  • partial or full blockages

✔ 2. To facilitate flushing and cleaning

The well has enough space for:

  • flushing hoses

  • cleaning tools

  • inspection cameras

✔ 3. For sampling

Taking samples directly from a pipe is difficult — the well provides a clean and safe sampling point.

✔ 4. To meet regulatory requirements

Many municipalities require inspection wells for new on-site wastewater systems.

đŸ§± How Is an Inspection Well Constructed?

An inspection well typically contains:

  • Well chamber (plastic or concrete)

  • Inlet and outlet — usually at the same height

  • Cleaning access at the bottom

  • Cover assembly (frame + lid), typically load class A15 or B125

  • Telescopic riser if height adjustment is needed

  • Rubber seals for watertight connections

Common diameters: 315 mm, 400 mm, 600 mm and larger.

đŸŸ© Where Are Inspection Wells Used?

  • On-site wastewater systems

  • Drainage systems

  • Stormwater systems

  • Small treatment plants

  • Pump stations

  • Municipal sewer networks

  • Industrial sites