Blocked drains are perhaps one of the most common problems in virtually any household. Be it a sink, basin or toilet, drains get blocked each day and cause a large amount of headaches. Pouring bleach down the sink works to a certain extent, but after a few years something has to be done to unblock it. And if you're in charge of a public building just like a school or then your drains are probably going to need a whole lot more than just bleach.
The best piece of advice when dealing with blocked drains is: don't try to unblock it yourself. Drainage services companies often find that when they are called out, they must cope with a much worse problem than it the client hadn't tampered with the drain themselves. Instead of just dealing with the blocked drain, they suddenly end up met with a blocked and damaged drain, creating a lot more work. This is not only frustrating for the drain clearance company, but eventually ends up costing the client much more.
There are two principle methods utilized by drain clearance companies to clear blocked drains. The foremost is manual rodding. https://www.mylocalservices.co.uk/Pipeline+Drainage+Solutions-Newcastle+Upon+Tyne-3203887.html is virtually what you think it is: using a long metal rod to manually clear any debris blocking the drain. It is useful where there is not much space, but amateur attempts at achieving this are one of the biggest causes of drain damage. It may sound like a spectacularly simple methodology, nonetheless it will be a lot more involved than one might assume.
The second, far more exciting technique is that of high pressure jetting. Again, the moniker given the technique makes a conclusion almost redundant. However, it is worth noting that high pressure water jetting is so effective that it's also used for a number of other applications, such as for example cleaning gum of pavements and car parks. If you find enough room to properly utilise it, high pressure jetting is the most effective way of clearing blocked drains, as it also cleans residue from the side of the drain which could otherwise eventually build-up into a blockage.
As such, ruthless jetting is a technique that's sometimes used pre-emptively to prevent blockages, rather than waiting for the drain to obtain blocked at all. That is particularly ideal for large public buildings where a blocked drain could easily spell disaster and lost working time.
Blocked drains is definitely an enormous headache. The great thing you can do to avoid further headaches in the future, is call a professional.