Clear, Practical Drawings for Water Hygiene Management

Understanding how water moves through a building is essential for effective Legionella control.

Large or complex buildings can contain multiple incoming supplies, storage tanks, booster sets, calorifiers, circulating hot water systems, point-of-use heaters and numerous branches serving different areas of the premises.

Source Water Compliance produces clear water system schematic drawings to support Legionella risk assessments, Written Schemes of Control, monitoring programmes and day-to-day water hygiene management.

Our drawings are designed to help facilities teams, Responsible Persons and contractors quickly understand the principal water systems and how they relate to the building.

Request a Water System Schematic

Discuss Your Water Systems

What Is a Water System Schematic Drawing?

A schematic drawing provides a simplified representation of the principal components and distribution routes within a water system.

It is not intended to replace detailed engineering or construction drawings.

Instead, its purpose is to show the parts of the system that are particularly relevant to water hygiene and Legionella control.

A useful schematic should allow somebody unfamiliar with the building to understand the main route of water through the premises without having to interpret complex mechanical drawings.

What Can Be Included?

Depending on the system, the schematic may show:

Incoming mains water supplies
Cold water storage tanks
Booster sets
Water softeners
Cold water distribution
Calorifiers
Hot water generators
Hot water flow and return systems
Point-of-use water heaters
Thermostatic mixing valves
Expansion vessels
Showers and higher-risk outlets
Sentinel outlets
Representative monitoring locations
Building levels or zones
Separate buildings or wings
Relevant isolation points
Other important water hygiene assets

The level of detail should reflect the purpose of the drawing and the complexity of the system.

Supporting Legionella Risk Assessments

A schematic drawing is particularly useful when produced alongside a Legionella risk assessment.

During the assessment, the water system can be traced from the incoming supply through storage, hot water generation and distribution to representative outlets.

The resulting schematic can then help illustrate:

where water is stored → how it is heated → how it is distributed → where it circulates → where monitoring takes place

This makes the findings of the assessment easier to understand and manage.

Supporting the Written Scheme of Control

A Written Scheme of Control describes how Legionella risks should be managed.

The schematic helps provide the visual reference behind those procedures.

For example, the Written Scheme may identify monitoring at a particular calorifier, tank or sentinel outlet.

The schematic can show where those components sit within the wider water system.

This is especially valuable on larger sites where several similar pieces of equipment may be present.

Identifying Monitoring Locations

Water hygiene monitoring is more useful when the locations being monitored are clearly identified.

A schematic can help show:

sentinel outlets

representative outlets

calorifier flow and return points

cold water storage locations

hot and cold water distribution zones

This can make routine monitoring more consistent, particularly where several engineers or contractors attend the same site.

Complex and Multi-Building Sites

Some sites contain several interconnected systems.

Examples may include:

main building → annex → sports centre → workshops → accommodation → remote facilities

Each building may have its own water heater, storage system or distribution arrangement.

A clear schematic can help show how these systems relate to one another and where responsibility or monitoring requirements differ.

This can be particularly valuable for:

Hospitals and healthcare estates
Schools, colleges and universities
Hotels
Industrial sites
Commercial buildings
Residential developments
Facilities management portfolios
Large multi-building estates

Understanding Hot Water Circulation

Large hot water systems can be difficult to understand from inspection alone.

A schematic can show:

calorifier → hot water flow → distribution risers → outlets → return circulation → calorifier

This can help facilities teams understand circulation routes and identify where temperature monitoring should take place.

Where a building contains several hot water zones or multiple calorifiers, the drawing can help distinguish one system from another.

Cold Water Storage and Distribution

Where cold water storage is present, the schematic can show how the tanks are supplied and what areas they serve.

This can include:

incoming mains → storage tank → booster set → distribution risers → building outlets

Where several tanks or booster sets serve different parts of the property, clearly identifying those relationships can be particularly useful during maintenance or investigation.

Updating Existing Drawings

Water systems frequently change.

Refurbishment, tenant alterations, replacement plant and changes in building use can mean older drawings no longer reflect the system that is actually present.

Source Water Compliance can review existing schematics and update them following site inspection.

This may be appropriate where:

New calorifiers have been installed
Tanks have been removed
Point-of-use heaters have replaced central systems
Buildings have been extended
Pipework has been modified
Tenant fit-outs have changed water services
Redundant equipment has been removed
Existing drawings are unclear or outdated

Keeping the schematic current helps ensure the risk assessment and Written Scheme remain meaningful.

Clear Drawings, Not Unnecessary Complexity

The purpose of a water hygiene schematic is clarity.

A drawing overloaded with every valve, fitting and pipe diameter can become difficult for facilities teams to use.

Our approach is to focus on the components and distribution routes that matter most for understanding and managing the water hygiene risk.

That means the drawing should be detailed enough to be useful without becoming unnecessarily complicated.

Useful During Investigations

Schematics can also be valuable when investigating issues such as:

Repeated temperature failures
Positive Legionella results
Poor hot water circulation
Excessive cold water temperatures
Stagnation
Low-use areas
System modifications
Unclear distribution routes

Being able to see the wider system can make it easier to understand whether a problem is isolated to one outlet or linked to a larger section of the distribution system.

Multi-Site Portfolios

For organisations responsible for several properties, using a consistent drawing style across the estate can make information easier to manage.

Source Water Compliance can produce schematics using a consistent format across hotels, commercial properties, education estates, healthcare sites, residential developments and FM portfolios.

This helps create a more uniform set of water hygiene documentation.

Supporting Services

Water system schematic drawings work particularly well alongside our:

Legionella Risk Assessments

Written Schemes of Control

Water Hygiene Audits

Water Hygiene Monitoring

Water Hygiene Maintenance & Servicing

Water Sampling & Microbiological Testing

Water Hygiene Consultancy

Those can all link internally to the service pages you’re building.

Arrange a Water System Schematic

If you require a new schematic drawing, need an existing drawing updated or want your water system mapped as part of a Legionella risk assessment, Source Water Compliance can help.

We can inspect the principal water systems and produce a clear schematic showing the key storage, generation, circulation and distribution arrangements.