“Can you just quote me for a non-return valve?”
We get enquiries like this all the time.
On the surface, it seems like a reasonable request? Someone has experienced backflow. Or flooding. Or a survey has flagged sewer surcharge risk. They have been told they need a non-return valve for Backflow Protection. So they approach a flood defence company and ask for a quote.
In theory, that makes sense.
In reality, this is where things start to unravel.
The first question we ask is simple.
• What stage is this actually at?
Then:
• Have you got a drainage plan or had a design completed?
• Do you know where the valve should go?
• Do you know what type of valve is needed?
• Has anyone assessed chamber depth, pipe diameter, access for maintenance, or ownership of the sewer?
Almost always, the answer is no.
The request is simply “can I get a quote”.
Here is the issue. To quote for a non-return valve installation, three things must already be known.
• It must be proposed/located in the correct place.
• It must be specified correctly.
• It must remain accessible for inspection and maintenance.
And to establish any of that, you first need to understand the drainage network at the site. What flows where. Are there any accessible inspection chambers. How deep are they. Which pipes serve which areas. Which manholes belong to the water authority. Where backflow actually occurs.
Without that information, a quote is not viable, or accurate.
Non-return valves themselves are not necessarily complicated pieces of kit. In some cases, the right solution is a simple push-fit valve installed into an existing chamber. The material cost can be under a hundred pounds. If that solves sewer surcharge into a toilet, that is a great outcome.
But we cannot know that without understanding the system.
And even a site visit does not always provide enough information on its own.
The proper starting point is always the same.
Understand the problem. Then engineer the solution.
That typically means:
• A CCTV drainage survey.
• A CON29DW search.
• A review of findings.
• Options development.
• A design.
• A design risk assessment.
Only after that stage can installation be proposed.
This is where expectations often clash with reality. Property flood resilience is frequently viewed like calling out a tradesperson to quote for a job. But it is not a trade exercise. It is an engineering process. When that distinction is missed, projects go wrong.
I have reviewed schemes where non-return valves were installed in the wrong location, leaving supposedly protected areas still at risk. I have seen flood walls built with no understanding of the drainage network underneath them. These mistakes are expensive. And entirely avoidable.
The underground infrastructure is the starting point.
Not an ad-hoc request to fit a valve.
We explain this process often. We even help clients obtain CCTV survey quotes to give a clearer picture of overall cost. Yet the response is frequently the same.
“I only wanted a non-return valve.”
“I did not realise it would be this involved.”
“I did not expect it to cost this much.”
If you already understand your drainage routes, and a simple push-fit valve achieves the outcome, brilliant. That is the best-case scenario. But in many properties the work involves excavation, new access chambers, pipe alterations, or on occasion, even installing new drainage. Groundworks cannot be fixed-price quoted blindly. Nobody knows what sits underground until it is investigated.
I fully support the push to mainstream property flood resilience. But some measures, especially non-return valves, need an engineer’s assessment first. Skipping that step is where money is wasted and protection fails.
So if you think you need a non-return valve, read this first.
We can probably help.
But it will rarely be a simple “quote to fit”.
And pretending otherwise would be doing you, and us, a disservice.
Below I’ve included a few photos to illustrate the variety of non-return valves that may be suitable at property level. Some are simple push-fit units for internal chambers. Others are designed for external access points or larger pipework. And for bigger sites, such as developments with outfalls to watercourses, entirely different and much larger systems are used.
Full Port Non-Return Valve in Inspection Chamber
Inline Non-Return Valve in Pipe
Push Fit Non-Return Valve
Wastewater Non-Return Valves
Outlet Flap Valves
Hopefully this helps demonstrate why it is rarely as simple as providing a quick quote. Non-return valves are an important tool in flood resilience, but only when they are correctly located, correctly specified, and properly integrated into the drainage network. That understanding has to come first.
Written by: Simon Crowther BEng (Hons) FCIWEM C.WEM MIET