Keeping drains in sound condition

Peter Stacey, honorary life president of the National Association of Drainage Contractors (NADC) gives some top tips for keeping the drainage system working.

Having spent over 50 years in the drainage industry dealing with emergency blockages within domestic, commercial, and industrial premises, it is a simple fact that the majority of blockages and flooding situations could easily have been avoided had simple precautionary measures been adopted.

Keep things clean & tidy

Keeping all external areas clean and tidy would minimise, if not avoid, many flood occurrences. When rainfall is present, any loose lying rubbish in open spaces can easily wash down and cover grids and fill gullies causing flooding directly into properties. Once water is able to enter a property, serious damage can occur to floors, carpets, furniture, and even affect the structure of the building itself. The point here is that everyone can contribute to helping reduce flooding by not littering and leaving rubbish in open spaces. But it goes beyond that. In a recent call out to clear a drain, it became obvious that wood chippings on top of a non-porous membrane on the side of a bank were responsible for a serious blockage. Whilst the blockage could be cleared, the problem will repeat itself time after time unless the membrane and wood chippings are removed, and the bank once again becomes able to absorb water. It could be suggested that an application of common sense in not installing the membrane and wood chippings in the first place would have avoided the problem. This holds equally to the increasing preponderance of installing concrete, paving or tarmac surfaces on gardens and driveways which often cause flooding issues.

Maintenance

Undertaking regular maintenance avoids problems before they happen. In the majority of emergency situations, blockages within drains, with the potential to cause flooding, frequently occur as a direct result of a lack of maintenance. An annual inspection of drains, either visual or with CCTV, and cleaning of the system as appropriate can save a lot of time and trouble. Inspection can also identify far more serious problems such as structural defects, which can include broken or damaged pipes, root ingress, or subsidence, and even identify the potential collapse of a drain itself. Early identification of these problems enables remediation before potentially catastrophic consequences may occur. Further, early detection of a problem and remediation can save a lot of money. The cost E F of a CCTV survey is very reasonable, and trenchless technology (using electro mech and/or milling, and patching or re-lining) to repair broken pipework can save massively on excavation and repair which may become inevitable in the case of a serious drain failure.

Fats, oil and grease (FOG)

FOG management is really important. The buildup of FOG in drains and sewers, when combined with the likes of wet wipes and sanitary towels, can cause blockages which cause severe damage. It is not just about fatbergs in major sewers (one in London weighed over 10 tonnes), blockages are most common in small bore pipework, often close to the source of the problem; most frequently restaurants and cafes.

Pouring hot fat or oil down a sink drain will almost inevitably lead to problems, and when hot water and detergents are not used during the washing of plates, pots and pans, the grease residue will not dissolve and cling to the side of pipes, creating a reduction in the outgoing pipe size. It is then that a blockage will occur with an attendant cost to rectify. Simple measures like scraping all food debris off plates, wiping any FOG residue off with a paper towel and throwing it in a bin, and then washing with hot water and detergent can make a big difference. Also, those food outlets that have grease interceptors (which help to separate grease from water and hold it in a reservoir) should have them emptied and serviced at least once a year. Ideally all food outlets should have grease traps fitted, and there is a strong argument that they should be legally required.

Infrastructure

Looking after major infrastructure is a must. Regular maintenance of highways, street gullies (and gully pots) and pipe networks can help prevent major flood events, but it is often neglected because of tight budgets and poor management. Lack of maintenance will not only lead to flood events, but also can result in potholes, which in turn yield debris being washed into already backed up systems. This can cause increased damage from road construction materials to the road and pipe infrastructure. This becomes a vicious circle ultimately causing more flooding to the surrounding environment. These days there are very sophisticated tankers with vacuuming and flush through capability that can maintain systems on a massive scale. This is at a very economic cost when set against the damage that surface water flooding can cause. The maintenance of major infrastructure in the public sector should be compulsory, with regular inspections being scheduled to ensure it happens. It should not be left to the vagaries of local short-term budgetary issues or poor management. Relatively economic investment in maintenance today can save vastly greater costs of remediating major flood issues in the future.

Another factor is the reliance on old infrastructure that can no longer handle the capacity required, an example being combined sewage and surface systems, which should be separated. Simple surveying techniques can identify such infrastructure allowing for targeted investment in remediation. Drainage contractors frequently come across such infrastructure and could be a valued resource in targeting investment to where it is needed most, and arguably this could form part of a Government-funded scheme.

In summary

So, what are the best practices that should be adopted to keep our drains and sewers flowing to minimise the risk of flooding?

Keep all open areas near drainage grid covers and gullies free from rubbish and leaves and use common sense before covering porous surfaces with non-porous materials.

Regularly inspect drains with CCTV to pre-empt blockages occurring and exercise diligence in not allowing FOG to enter the drainage system.

Only use toilets for the purpose for which they are designed – the three Ps (pee, poo and paper).

Empty and service interceptors and gully collection pots on a regular basis and manage major infrastructure properly, maintenance is an investment into the future.

Legislate where necessary that inspection and maintenance are undertaken on a regular scheduled basis and remediate old infrastructure before it becomes a problem.

Finally, make sure you always use the services of a reputable NADC/DrainSafe contractor 
who will not only do a professional job, but 
also give you tailored advice to avoid problems in future!