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Klargester Gamma Septic Tank 3500L Single Stage - 10 Person

Over 17,000+ Happy Customers

Klargester Gamma Septic Tank 3500L Single Stage - 10 Person

£1,424.50

(exc VAT)
£1,424.50

(exc VAT)
£1,611.50
Quantity

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This product is delivered directly from the supplier, lead times vary.

 

The Klargester 3500 Litre Gamma Septic Tank (Twin Stage) is a durable, cost-effective solution for domestic properties that are not connected to the mains sewer network. Designed to provide reliable primary wastewater treatment, this high-quality septic tank is ideal for households seeking an efficient and low-maintenance off-mains drainage system.

Manufactured from robust medium-density polyethylene (MDPE), the Klargester Gamma septic tank offers excellent strength, corrosion resistance and longevity while remaining lightweight for easier transportation and installation. Its twin-stage design helps improve settlement and separation of solids, delivering dependable performance for residential wastewater management.

With a 4000-litre storage capacity, this septic tank is suitable for properties with up to 10 people, making it an excellent choice for larger homes, small developments and rural properties. The tank comes complete with a cover and frame and features a 1m invert depth as standard, helping to simplify installation and reduce additional site work.

 

Key Features

  • 3500-litre capacity septic tank
  • Suitable for populations of up to 10 people
  • Efficient twin-stage settlement design
  • Durable and corrosion-resistant MDPE construction
  • Lightweight for easier handling and installation
  • Ideal for domestic off-mains drainage systems
  • Supplied complete with cover and frame
  • 1m invert depth as standard
  • Reliable, low-maintenance operation
  • Trusted Klargester quality and performance

 

Find out everything a new septic tank owner needs to know here.

Installing a septic drain field? Find out everything you need to know here.

 

Unit Storage Volume (Ltr) Dim 'A' (mm) Dim 'B' (mm) Dim 'C' (mm) Dim 'D' (mm) Dim 'E' (mm) Dim 'F' (mm) Dim 'G' (mm) Dim 'H' (mm) Tank Weight
GST028TzGK 2800 500-1000 1255 550-1050 1205 2480 1130 1450 735 250 Kgs
GST035TzGK 3500 500-1000 1255 550-1050 1205 3000 1180 1450 735 280 Kgs
GST040TzGK 4000 500-1000 1255 550-1050 1205 3360 1215 1450 735 310 Kgs

 

Unit 1 2 3 4
GST028TzGK 315mm 460mm 460mm 315mm
GST035TzGK 315mm 800mm 800mm 315mm
GST040TzGK 315mm 900mm 900mm

315mm

 

 Gamma Septic Tank PIA Certificate

Gamma Septic Tank Twin Stage Gravity Drawing

SKU: TANSEPTKLA017

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Tanks ship direct from the manufacturer, with lead times varying by product.

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Need help choosing the right tank? Call our team on 01388 537050.
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CUSTOMER REVIEWS

Rated 4.8/5 by Direct Drainage Customers

Based on over 600 verified reviews

VERIFIED REVIEW

Very helpful from the start to the finish

Items were despatched quickly and arrived the next day. Would recommend.

Title

North Hayne Farm Cottages | 26 June 2026

VERIFIED REVIEW

Cheapest price I could find for the pump

Cheapest price I could find for the pump and delivery the next day what more could you want.

Title

Sam Jukes | 5 November 2025

VERIFIED REVIEW

Great service!

I ordered a septic tank it was delivered within a week and the delivery driver left it in the exact right place and time. Would definitely use this company again, thanks so much.

Title

Eve Harland | December 2025

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FAQs

Got questions? We’ve got the answer...

When will my order be dispatched?

Spare Parts Shipping
We ship in-stock spare parts the same day if ordered before 3pm. These orders are sent with DPD as standard and will be shipped on a Tracked Next-Day service.


Tanks & Supplier-Shipped Items

Tanks and certain spare parts are shipped directly from our suppliers. We aim to submit supplier orders to the supplier on the same day your order is placed to ensure prompt processing. 

How much is delivery?

Delivery costs vary depending on the type of product:

 

In-stock Spare Parts: £8.20 - shipped via DPD on a Tracked Next-Day service.
Supplier-shipped Spare Parts: £15 - dispatched directly from the supplier.
Tanks and Sewage Treatment Systems: Free Delivery to most mainland UK postcodes.

 

All delivery charges are calculated accurately at checkout.

I need help with placing my order.

No problem! Here are a few ways we can assist you:

Live Chat: Click the chat icon on the bottom right of the page to speak with our team instantly.
Call Us: Reach us at 01388 537050 during business hours for quick support.
Email: Send your query to sales@direct-drainage.co.uk, and we’ll respond promptly.

Do you stock all tanks and sewage treatment systems?

We do not stock tanks and treatment systems as standard. These are supplied directly from the manufacturer. The lead times of these systems will vary. If you need an accurate delivery date, please contact us on 01388 537050.

Are your prices inclusive of VAT?

It is important to note that all prices listed on our website exclude VAT. VAT will be calculated at checkout. 

I've found the same item somewhere cheaper, can you match the price?

We always aim to offer competitive pricing. If you've found the same item cheaper elsewhere, let us know — we'll do everything we can to match or even beat the price.

 

Contact us directly on 01388 537050 or drop us an email at sales@direct-drainage.co.uk.