Leading septic tank installation company in Hertfordshire. We install septic tanks, sewage treatment plants, carry out percolation testing and fit rainwater harvesting & attenuation tanks across Hertfordshire.
As a specialist septic tank installation company, Flowcraft handles everything from new septic tank installations and septic tank replacements to sewage treatment plant systems and waste water treatment plants. Many properties across Hertfordshire and surrounding areas are not on mains drainage, making off-grid drainage solutions one of our core specialities.
Not sure what happens inside the tank? Read our guide: What Is a Sewage Treatment Plant?
We undertake percolation testing to ascertain which drainage systems are suitable for your property. This essential assessment determines soil permeability and guides the design of septic tanks, sewage treatment plants, soakaways and drainage fields, ensuring a compliant and effective solution tailored to your site conditions.
The correct treatment and discharge arrangement depends on the site. Our General Binding Rules guide explains when a discharge can operate without an individual environmental permit.
The receiving ground is part of the system. Read What Is a Drainage Field? before planning a new or replacement installation.
In addition to septic and sewage systems, we also install rainwater harvesting tanks and attenuation tanks, helping you manage surface water responsibly, reduce runoff and lower water bills. We work with both domestic and commercial clients, ensuring every installation meets current regulations. After every septic tank or treatment plant installation, we provide premium reinstatement and landscaping, leaving your property in better condition than we found it.
Buying or selling a property with an existing private wastewater system? Learn more about our Private Drainage & Wastewater Surveys.
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Identify blockages, damaged pipework and issues on the inlet or outlet of an existing septic tank or treatment plant.
Locate and map hidden foul runs feeding into the tank — essential before replacements, upgrades or connecting new drainage.
Buying a property with a septic tank or treatment plant? A CCTV survey is one of our most requested checks before completion.
We'll review your message and photos, then follow up by phone or email to discuss your project in more detail and arrange a convenient time for a site visit.
Our experienced team carries out the work efficiently and to the highest standards, from septic tanks and drainage to civil engineering and groundworks.
Send us a WhatsApp message with a brief overview of what you need and, if possible, a few photos. This helps us understand the scope quickly and get back to you with the right advice.
We visit your property to fully assess the requirements and provide a detailed, no-obligation quote. For complex jobs, we may visit twice to make sure every detail is covered.
We don't just do the job and leave. We reinstate your site with quality landscaping, leaving it better than we found it. That'''s the Flowcraft difference.
Send us a WhatsApp message with a brief overview of what you need and, if possible, a few photos. This helps us understand the scope quickly and get back to you with the right advice.
We'll review your message and photos, then follow up by phone or email to discuss your project in more detail and arrange a convenient time for a site visit.
We visit your property to fully assess the requirements and provide a detailed, no-obligation quote. For complex jobs, we may visit twice to make sure every detail is covered.
Our experienced team carries out the work efficiently and to the highest standards, from septic tanks and drainage to civil engineering and groundworks.
We don't just do the job and leave. We reinstate your site with quality landscaping, leaving it better than we found it. That'''s the Flowcraft difference.

Drop us a WhatsApp with a quick description and some photos. We'll review everything and get back to you to arrange a site visit.
Call, WhatsApp or email anytime