Sizing Your Waste Water System: The Essentials

Accurate sizing ensures efficiency, compliance, and longevity.

✅ For domestic properties:

Number of people = Bedrooms + 2.

Add 1 per extra bedroom.

For example: 4-bedroom house = 6-person system.

✅ Soakaway design:

Use a percolation test (Part H) to determine subsoil permeability.

Size soakaway accordingly – or choose a system with direct discharge approval.

Waste Water Supplies can help assess this for you, or you can call us on 01296 841007 for tailored guidance before buying.

🛠️  Best Practice Installation Tips

 

⚠️ Before You Dig:

Check for permits – Environmental Permitting Regulations (EPR) may apply.

Consult the EA if discharging to a ditch, stream or land.

✔️ Base prep:

Concrete base required for most STPs.

Follow manufacturer’s depth, ventilation, and access guidelines.

🌀 Ventilation:

Crucial to avoid odours and gas buildup.

Use vent pipe and carbon filter kits where needed.

🔌 Electrics:

Keep control panels dry and accessible.

Consider UPS or alarm systems for critical applications.

🌧️ Groundwater risks:

If high water table: consider ballast kits or anti-floatation slabs.

Some systems like Graf or Marsh tanks are designed for high groundwater areas.

🔧 Servicing & Aftercare

Annual servicing is often a requirement to retain discharge permits.

Desludging intervals: 6–12 months depending on usage.

Keep spares like air pumps, diffuser membranes, and floats handy – Waste Water Supplies stocks all these.

📊 Comparison Table