Water Levels

About Water Levels

Water levels, also known as water tube levels or hydrostatic levels, are simple yet incredibly accurate levelling tools that use the fundamental principle of water always finding its own level. These ingenious devices consist of a transparent tube filled with water, allowing tradespeople to establish perfectly level reference points across long distances, around corners, and even between separate rooms or floors. Unlike spirit levels or laser levels that require line of sight, water levels excel in situations where obstacles or building features would otherwise make accurate levelling extremely challenging.

The beauty of a water level lies in its simplicity and reliability. With no batteries to run flat, no electronics to malfunction, and no calibration required, these tools have been trusted by builders, bricklayers, and groundworkers for generations. Modern versions, such as those from Faithfull, typically feature clear graduated tubing with measurement markings, allowing users to not only establish level but also measure height differences accurately. They're particularly valuable for foundation work, setting out building levels, installing suspended ceilings, establishing drainage falls, and any application where precise levelling is required over distances that would be impractical for conventional spirit levels.

Water levels are especially popular on building sites where cost-effective accuracy is paramount. While laser levels have become more common, many experienced tradespeople still keep a water level in their toolkit as a reliable backup that will never let them down, regardless of weather conditions, battery life, or accidental knocks. They're also ideal for DIY enthusiasts tackling projects like patio laying, fence installation, or decking construction where professional accuracy is needed without the investment in expensive electronic equipment.

Jargon Buster

• Hydrostatic Levelling: The scientific principle that water in a connected system will always settle at the same height, regardless of the shape or route of the connecting tube. This fundamental property of fluids makes water levels possible.
• Datum Point: A fixed reference point from which all level measurements are taken. When using a water level, you establish a datum and then transfer that exact level to other locations.
• Graduated Tubing: Clear plastic tubing marked with measurement increments (typically in millimetres), allowing you to read height differences as well as simply establishing level points.
• Air Bubbles: The enemy of accurate water level readings. Any air trapped in the tube will affect accuracy, so proper filling and priming is essential before use.
• Fall/Gradient: A deliberate slope required for drainage purposes. Water levels can be used to calculate and mark consistent falls by measuring the height difference between two level points.
• True Level: A perfectly horizontal plane. Unlike spirit levels which can be affected by viewing angle or surface irregularities, water levels provide true level referenced to the earth's gravitational field.

Who Uses Water Levels?

Water levels are essential tools for a wide range of construction and landscaping professionals, including:

• Bricklayers and Blocklayers: For setting out building levels, establishing course heights, and ensuring foundations are perfectly level across long wall runs
• Groundworkers: Essential for foundation work, drainage installation, and establishing site levels before construction begins
• Landscapers: Perfect for patio laying, retaining wall construction, decking installation, and establishing drainage falls in garden projects
• Builders and General Contractors: Used throughout construction projects for setting out, establishing floor levels, and coordinating work between different trades
• Plasterers and Ceiling Fixers: Ideal for establishing datum lines for suspended ceilings and ensuring consistent ceiling heights throughout large buildings
• Fencers: For establishing consistent post heights and ensuring level rails across uneven terrain
• Plumbers and Drainage Specialists: Calculating required falls for drainage pipes and establishing correct gradients for waste systems
• DIY Enthusiasts: Homeowners tackling garden projects, shed bases, greenhouse installations, or any levelling work requiring professional accuracy on a budget

How to Choose the Right Water Levels

Selecting the appropriate water level for your needs involves considering several practical factors:

Length and Reach: Water levels are available in various lengths, typically from 10 to 30 metres or more. Consider the maximum distance you'll need to work across. For domestic work and small sites, 10-15 metres is usually sufficient, whilst larger construction projects may require 20-30 metre lengths. Remember, the tube should be long enough to reach comfortably between your furthest points without stretching tight.

Tube Quality and Clarity: Look for clear, high-quality PVC or polyurethane tubing that won't discolour or become brittle over time. The tube should be transparent enough to see the water level clearly, with good graduated markings that won't wear off. Thicker-walled tubing resists kinking and is more durable on active building sites.

Measurement Graduations: Better quality water levels feature clear millimetre graduations along the tube, allowing you to measure height differences as well as simply establishing level. This is particularly useful for calculating drainage falls or setting multiple level points at different heights.

End Fittings: Some water levels come with protective end caps or mounting clips that make single-person operation easier. These allow you to secure one end whilst you work at the other location, rather than needing a second person to hold both ends.

Storage and Portability: Consider how the water level is supplied – better sets come with storage reels or cases that prevent tangling and protect the tube between uses. A compact storage solution is essential for keeping the tool in good condition and ready for use.

Budget Considerations: Water levels are generally inexpensive tools, with most professional-quality options available at very reasonable prices. Given their reliability and longevity, investing in a good quality unit from a reputable manufacturer like Faithfull represents excellent value, often lasting for decades with proper care.

Popular Accessories

• Spirit Levels: Whilst water levels excel at long-distance levelling, traditional spirit levels are essential for shorter distances and checking plumb. The two tools complement each other perfectly in any toolkit.
• Chalk Lines: After establishing level points with your water level, chalk lines allow you to snap straight reference lines between them for marking out courses or guidelines.
• Measuring Tapes: Essential for working alongside your water level to measure heights and distances accurately when establishing multiple datum points.
• Line Pins and String: For transferring level marks around corners or creating temporary guidelines between established level points.
• Food Colouring or Level Dye: Adding a few drops of food colouring to the water makes the meniscus much easier to see, particularly in bright sunlight or when working at a distance.
• Builder's Pencils and Markers: For marking the established level points on walls, posts, or formwork once you've transferred the level.

Safety Information

Whilst water levels are inherently safe tools with no moving parts or electrical hazards, some practical safety considerations apply:

Always ensure the tube is securely positioned and won't create a trip hazard across walkways or working areas. On busy sites, clearly mark or protect the tube route to prevent damage and potential accidents. When working at height to establish level points, always use appropriate access equipment such as stepladders or tower scaffolds that comply with HSE guidelines for working at height.

Be cautious when filling the water level, particularly if using a tap or hose – ensure all air bubbles are purged before taking readings, as trapped air will affect accuracy. If adding food colouring to improve visibility, use only a few drops and avoid spillage on finished surfaces or clothing.

Store your water level properly after use, ideally drained of water to prevent algae growth or deterioration of the tube. Ensure it's coiled carefully without tight kinks that could cause permanent damage to the tubing.

Frequently Asked Questions

How accurate are water levels compared to spirit levels or laser levels?

Water levels are extremely accurate, typically to within ±1-2mm over 30 metres, which matches or exceeds the accuracy of many electronic levels. Their accuracy is based on fundamental physics rather than mechanical or electronic components, making them inherently reliable. Whilst laser levels offer convenience for line-of-sight work, water levels excel in situations where you need to level around corners, between floors, or across obstacles where lasers cannot reach.

Can I use a water level in cold weather?

Yes, but with precautions. In temperatures approaching freezing, consider adding a small amount of methylated spirits or antifreeze to the water to prevent freezing. However, this may slightly affect the water's surface tension, so use the minimum amount necessary. In very cold conditions, standard tap water works fine provided temperatures stay above freezing during use.

How do I remove air bubbles from my water level?

Fill the tube slowly from one end, holding it in a U-shape to allow air to escape as water fills from the bottom. Alternatively, fill it completely, seal both ends, then hold it vertically and tap along its length to encourage bubbles to rise to the top. Remove the top seal briefly to release trapped air. For stubborn bubbles, running water through the tube whilst holding it at various angles usually clears them completely.

What length water level do I need for garden and patio projects?

For most domestic projects, including patios, decking, and garden landscaping, a 10-15 metre water level is perfectly adequate. This length allows you to work across typical garden dimensions whilst being manageable to handle and store. If you're working on larger plots or need to establish levels across multiple garden features, a 20-30 metre version offers greater flexibility.

Can water levels be used to calculate drainage falls?

Absolutely – this is one of their most valuable applications. First, establish true level at both ends of your drainage run using the water level. Then measure down from these level marks by the required fall amount (typically 1:40 to 1:80 for drainage depending on pipe diameter and building regulations). Water levels with graduated tubing make this calculation straightforward, and the method is far more reliable than trying to calculate falls using spirit levels over long distances.