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When To Instruct a Drainage Survey for Commercial Property

The real risks lie in areas not seen without an underground inspection. 

If there is an investment into commercial property of any kind, or asset performance is relied upon, leaving the condition of the drains to chance risks undermining the entire intended investment purpose.

Protecting Investment Starts Below Ground

Early inspection can proactively mitigate unexpected shocks down the line. If defects are ignored, they always deteriorate over time, resulting in: 

• Greater remedial costs
• Increased disruption to operation
• Elevated risk of pollution or other areas of legal non-compliance 

It is not just the structural defects that can cause significant problems. Other issues you cannot see can occur, such as:

• Environmental risk
• Legal non-compliance
• Capacity limitations
• Long term maintenance requirements 

These issues are not addressed in a standard CCTV survey. However, as we understand the needs of the industry, our transactional drainage assessment evaluates every factor relating to the system. 

Due to the severity and potential long-term impact of these risks, specialist advice is essential to evaluate the site’s vulnerability and determine tailored solutions that act in the site’s best interests.

Warning Signs 

Whilst many costly drainage defects remain hidden until significant damage has occurred, there are sometimes early warning signs above the surface that can indicate a drainage problem. 

Potential warning signs include:

• Ground movement
• Rising damp 
• Cracked walls
• Uneven, cracked or raised pavements 
• Sink holes appearing 
• Standing water
• Filled drains

Taking action early helps minimise costs and operational disruption, as defects in their early stages can typically be resolved with less invasive and more manageable solutions. 

However, as previously noted, many drainage liabilities are not visible from the surface so these signs alone should not be used as a basis for deciding whether a drainage survey is required.

Visible Indicators

There are also visible surface indicators that signal the need for a drainage inspection. These features can suggest a lack of maintenance, pose operational issues, or present potential environmental and regulatory risks.

If you identify one of the following on a site, it is best to instruct a drainage inspection: 

• Debris down the drains

Sign of lack of maintenance and therefore, potentially hiding liabilities. 

• Seized manholes 

Sign the drains haven’t been accessed, therefore, a lack of maintenance and potentially concealing underlying liabilities. 

• Oil storage on site 

If incorrectly stored or a spillage occurs, it can result in pollution. If there are no oil interceptors on site and oil is stored, there is a very high chance of pollution.

• Chemical storage on site

If incorrectly stored or a spillage occurs, it can result in pollution.

• Trees are positioned near the drains

Indicate there is a risk of root ingress and therefore, reduced capacity and defects in the pipework – potentially resulting in a collapse. 

• Buildings were built before 1980s

Pitch fibre drains were commonly used between the 1940s and 1970s as they were cost-effective and easy to install. However, they have a lifespan of about 40 years and are prone to issues such defects and collapse so can be a severe hidden liability for older buildings.   

• Pressure washers/vehicle wash downs on site

It is illegal for these to discharge into a surface water sewer yet this is commonly seen on commercial sites. Our drainage inspection will highlight if this feature is compliant and if not, we can advise on the most suitable remedial method. 

• Septic tank or treatment plant

It is against the law to not maintain these systems or operate them incorrectly. If the site shows signs of poor maintenance, there is a high chance this system is operating non-compliantly. 

• If the site is in a Ground Water Source Protection Zone (GWSPZ)  

The consequences of pollution in a GWSPZ are even more severe as the contamination impacts drinking water and can have irreversible consequences. Particularly if the site has soak-away drains, pollution is large risk. 

However, as previously mentioned, many drainage liabilities are not visible from the surface so theses signs alone should not be used as a basis for deciding whether a drainage survey is required. 

The drainage system should always be inspected. Even if from the surface there seems to be no issues, the majority of issues are not visible from the surface. You cannot know what is going on beneath the ground without an inspection, and ignoring the drainage system is a big risk to take. 

Whether you are acquiring, disposing, managing or refurbishing a commercial asset, drainage liabilities should never be left to chance. Failure to understand the true condition of the system compromises the intended purpose of the investment.

Prevention is always better than a cure

Furthermore, taking action early helps minimise costs and operational disruption, as defects in their early stages can typically be resolved with less invasive and more manageable solutions.

Trying to cut costs in the immediate term only results in greater costs and issues later down the line. At some point, the drainage system is going to require attention, and the sooner risks are found, the less costly the remedial work is generally going to be.