Site Levels
Ensuring Your Drains Flow Downhill
It sounds obvious, but for drainage to work, water needs to flow downhill. If your pipes are laid too flat, or if the ground slopes the wrong way, the water will stagnate, leading to blockages and flooding.
Site Levels is the professional service where we measure the exact heights of your ground and your pipes to ensure gravity can do its job.
In simple terms: We use laser equipment to map the slope of your land and drains. This tells us if the water is flowing the right way—and helps us design the perfect solution if it isn’t.
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Why Do We Need to Check Levels?
You can’t “eyeball” a drainage gradient; it needs to be precise. Customers typically ask us to check levels when:
- Planning an Extension: You need to know if your new bathroom or kitchen can connect naturally to the existing sewer, or if the pipes are too shallow.
- Fixing Flooding: If water pools on your patio or driveway, we need to prove if the ground is sloping towards your house instead of away from it.
- Diagnosing Blockages: If a drain blocks repeatedly, it might have a “backfall” (where the pipe slopes the wrong way, forcing water to run uphill).
- Installing Soakaways: We must ensure the soakaway is positioned lower than the house drains so it actually accepts the water.
- Connecting to the Public Sewer: If you are looking to connect to the public sewer network, you will need to know if you can achieve the gradient via gravity fall or if a pumped system is required.
How We Measure It: The Process
We don’t just guess. We use a structured process and professional surveying tools to create an accurate picture of your system.
1. The Initial Assessment – First, we walk the site to identify the key points that matter. We look for manholes, drainage connection points, location of facilities within the property, and the proposed location for any new extensions or soakaways.
2. Laser Precision Measuring – We use professional laser levels or digital levelling tools to record accurate height data. We aren’t just measuring the surface; we are measuring two critical points:
- Cover Level: The height of the ground or the manhole lid.
- Invert Level: The depth of the inside bottom of the pipe. This is the most important number because it is where the water actually flows.
3. Calculating the Gradient (The Math) – Once we have the “Invert Level” from several different manholes, we compare them. This allows us to calculate the Gradient (or “Fall”).
- Example: If Manhole A is higher than Manhole B, we calculate if the slope is steep enough (e.g., 1:40 or 1:80) to carry waste away efficiently.
4. Analysing the Flow – We look at the bigger picture. Is the water flowing away from the building? Is there a low spot in the garden where water naturally gathers? If you are planning a new build, we check if the existing drains are deep enough to pass under the new foundations.
5. The Report – You receive a clear summary of our findings. We provide the measured levels, highlight any issues (like pipes flowing the wrong way), and give recommendations for how to fix them or how to design your new extension.
Common Issues We Find
A site levels survey often reveals the “invisible” causes of drainage misery:
- Backfalls: Pipes that have been installed sloping the wrong way, forcing water to fight gravity.
- Bellies: Pipes that have sagged in the middle, holding water like a trough even when not in use.
- Shallow Drains: Pipes that are too close to the surface to be built over safely without protection.
- Negative Surface Gradients: Driveways or patios that direct rain into the garage rather than a gully.
Who Is This For?
- Homeowners: Investigating mysterious flooding or planning renovations.
- Architects & Builders: Needing accurate data to design foundations and compliant drainage plans.
- Landscapers: Ensuring a new garden design won’t cause waterlogging.
The Benefits
- Avoid Mistakes: Prevents you from building an extension that can’t be connected to the sewer.
- Stop Flooding: Identifies exactly why water is pooling so it can be corrected permanently.
- Compliance: Ensures your new drains are installed to Building Regulations standards.
- Cost-Effective: It is much cheaper to measure twice and dig once!
Get the levels right, and the drainage will follow. Let ASL measure up your project
Correct levels are essential for a reliable drainage system — ASL provides clarity before work begins.
Testimonials
What Our Clients Say
“I called at 08:10 hours to report a blocked drain. A little while later, Darren rang to tell me he’d arrive in half an hour. He arrived on time and resolved the problem quickly and without fuss. He was polite and friendly throughout. Within two hours of reporting the blockage, all was well. Thank you.” Customer, Surrey
“I unreservedly recommend ASL. All the glowing reviews of ASL are true. They had to lift paving slabs to fix my drains, and I was concerned there might be unavoidable damage. I should not have worried. Liam and Richard did a superb job. Thanks, ASL” Customer, Surrey
“Darren arrived very promptly and got to work quickly. He did an excellent job and explained what he was doing. We would have no hesitation in recommending ASL Services.” Customer, Surrey
“Very efficient to book them to sort out a sewer drain blockage, and the cost was exactly what they quoted. Called before they arrived with a clear ETA. Got on with the job and sorted it out within the hour. Darren was excellent – very courteous and helpful, did more than we expected to help sort the problem out and was a font of knowledge on all things sewer-related. Given the subject matter (eeew) the whole experience with ASL was an absolute pleasure.” Customer, Surrey
“ASL recently carried out a drain repair at our house. They responded quickly to the call for help, came out and soon diagnosed the problem – tree roots blocking the drain. The remedial work on site was carried out by Lester and George – they worked hard and were very thorough. This is a long-established company that seems to know what they are doing.” Customer, Surrey
Areas we cover
Surrey, Hampshire, Berkshire, West Sussex and South West London
The ASL Limited HQ is in Guildford, but our operating area is the whole of Surrey and parts of Berkshire, Hampshire, West Sussex and South West London.
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Contact Us
Get in touch today
You can call us on 0800 181 684, email info@asllimited.co.uk or use the form below:
