Water Levels

About Water Levels

Water levels, also known as hydrostatic levels or water tube levels, are elegantly simple yet remarkably accurate levelling tools that have served the construction industry for generations. Based on the fundamental principle that water in a connected system always seeks its own level, these devices consist of a transparent tube filled with water that allows 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 an unobstructed line of sight, water levels excel in situations where obstacles, building features, or complex layouts would otherwise make accurate levelling extremely challenging.

The beauty of a water level lies in its simplicity and unwavering reliability. With no batteries to run flat, no electronics to malfunction, and no calibration required, these tools provide consistent accuracy regardless of weather conditions or site environment. Modern versions typically feature clear graduated tubing with measurement markings, allowing users to not only establish level but also measure height differences accurately—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.

Tooled-Up.com stocks professional water levels from trusted manufacturers like Faithfull, designed for single-handed operation when simultaneously measuring equal heights at two distant points. While laser levels have become more common on construction sites, many experienced tradespeople still keep a water level in their toolkit as a reliable backup that will never let them down. 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 is what makes water levels possible and provides their exceptional accuracy.
• 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, ensuring consistency across your entire project.
• 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. This feature is essential for calculating drainage falls and multi-level layouts.
• 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. Professional tradespeople always check for and remove air bubbles before taking measurements.
• 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, ensuring proper drainage in accordance with building regulations.
• 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, making them inherently more reliable for precision work.

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 where spirit levels would be impractical.
• Groundworkers: Essential for foundation work, drainage installation, and establishing site levels before construction begins, particularly on sloping or uneven terrain.
• Landscapers: Perfect for patio laying, retaining wall construction, decking installation, and establishing drainage falls in garden projects where precision is paramount.
• Builders and General Contractors: Used throughout construction projects for setting out, establishing floor levels, and coordinating work between different trades across multiple rooms or floors.
• Plasterers and Ceiling Fixers: Ideal for establishing datum lines for suspended ceilings and ensuring consistent ceiling heights throughout large buildings without line-of-sight limitations.
• Fencers: For establishing consistent post heights and ensuring level rails across uneven terrain where traditional levels cannot easily span the distances involved.
• Plumbers and Drainage Specialists: Calculating required falls for drainage pipes and establishing correct gradients for waste systems in compliance with building regulations.
• 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

Length and Reach: Water levels are available in various lengths, typically from 10 to 30 metres. 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. The tube should be long enough to reach comfortably between your furthest points without stretching tight, which can affect accuracy.

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 in various lighting conditions, with good graduated markings that won't wear off. Thicker-walled tubing resists kinking and is more durable on active building sites where tools take a beating.

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, eliminating the need for separate measuring equipment.

End Fittings and Features: 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—a significant advantage on sites where labour is limited.

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, particularly if transporting between multiple sites.

Budget Considerations: Water levels are generally inexpensive tools, with most professional-quality options available at very reasonable prices. The selection at Tooled-Up includes reliable options from manufacturers like Faithfull, representing excellent value given their reliability and longevity—often lasting for decades with proper care.

Popular Accessories

• Spirit Levels: Whilst water levels excel at long-distance levelling, traditional spirit levels from brands like Stanley and Bahco are essential for shorter distances and checking plumb. The two tools complement each other perfectly in any professional 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 on walls and foundations.
• Measuring Tapes: Essential for working alongside your water level to measure heights and distances accurately when establishing multiple datum points across complex layouts.
• Line Pins and String: For transferring level marks around corners or creating temporary guidelines between established level points, particularly useful in bricklaying and groundwork applications.
• 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 from the tube.
• Builder's Pencils and Markers: For marking the established level points on walls, posts, or formwork once you've transferred the level, ensuring marks remain visible throughout the construction process.
• Laser Levels: For line-of-sight applications, laser levels from Makita, DeWalt, or Bosch complement water levels perfectly, with each tool excelling in different situations.

Safety Information

Whilst water levels are inherently safe tools with no moving parts, electrical hazards, or power requirements, some practical safety considerations apply to their use on construction sites.

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—never overreach or work from unstable platforms.

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 and potentially compromise the safety of structural work that relies on those measurements. 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, rendering the tool unreliable for future use. Inspect the tube regularly for damage, splits, or deterioration, particularly if stored in direct sunlight or extreme temperatures.

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. Never leave water in the tube overnight during winter months.

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 without becoming unwieldy.

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 where cumulative errors can occur.