Main Drain Connections & Pumping Stations: What You Need to Know

When a private dwelling or commercial property needs to connect to the public sewer, it isn’t always straightforward. Your local water authority is responsible for the public sewer in the road, and when they install the main line, they aim to leave it at a level that allows nearby properties to connect using gravity.

But in practice, not every home is built at the right level. Some properties sit too low, or too far back from the main road, to rely on a natural downhill gradient.

Why Gradient Matters

A drain laid with insufficient fall (too shallow or no gradient at all) becomes problematic very quickly. Wastewater can back up, flow slowly, and create blockages.

One Reliable Solution: Pumping Stations

A pumping station compensates for lack of fall. Waste is pumped up into an inspection chamber located a few metres away from the public sewer. From there, the sewage runs into the main sewer in the road by gravity.

Types of Pumping Stations

Concrete ring stations

• Built from robust concrete rings.
• Sealed with tarred rubber joints to allow small ground movements without leakage.
• Little or no extra concrete surround is needed.
• Durable and dependable — unlike some plastic or glass-fibre tanks, which can fatigue and crack over time.     
• Concrete stations are often the preferred choice for long-term reliability.

Common Pumping Station Issues

Even the best-built pumping stations need correct use and maintenance. Here are two of the biggest issues we encounter:
 

1. Fat and grease build-up
    
   • Even a few millimetres of kitchen grease each week can cause problems.
   • Over time, fat coats the float switch, stopping it from working properly.
   • The result: the pump won’t switch on (risking flooding) or won’t switch off (running constantly, wasting electricity, and wearing out early).
      
2. Surface water ingress
    
   • Roof water or surface water entering the sewer can overwhelm a pumping station.
   • Direct downpipes are often easy to spot and remove.
   • Indirect surface water connections are trickier, especially for a busy contractor who may be tempted to “sign off” too quickly.
   • The proper way to test is to simulate heavy rainfall — e.g. using at least 2,000 litres of water on a four-bedroom house — to trace where roof water may be entering the system.

Why This Matters to You

Getting your main drain connection right isn’t just about compliance with your water authority — it’s about peace of mind. A correctly installed pumping station:

• Prevents costly backups.
• Protects against premature equipment failure.
• Keeps energy bills down.
• Ensures your system runs smoothly for years to come.
   

At ASL Limited, we’ve installed and maintained pumping stations for decades. We know the pitfalls — and how to prevent them.

✅ Next Step

If you’re planning a new main drain connection, or you’re concerned about an existing pumping station, get in touch with our team. We’ll assess your site, explain your options, and make sure your system is designed to last.