One of the most common plumbing problems we are called out to manage in Melbourne are slow running drains. Bathroom and kitchen sinks are particularly susceptible to this problem as they are heavily used (and misused). In this blog, we’ll take a look at the most common reasons that drains run slowly, how to work out which issue your drain is afflicted with, and how to fix the problem.

Factors that make a drain run slowly

  1. Fat

By far the most common cause of kitchen sink blockages is the build-up of congealed fat in the piping. The problem starts when fats and oils are disposed of down the sink and congeal on the sides of the piping. Over time, this sticky mess catches other debris that gets poured down he drain like coffee grains, tea leaves and undissolved food articles to create a physical block.

  1. General gunk

The bathroom version of a kitchen fat blockage occurs when soap scum sticks to the sides of the piping and then collects a nasty combination of hair, skin, and general dirt to create the clog.

  1. Physical objects

This type of blockage is another type of physical blockage which usually occurs when people put objects that cannot be dissolved or broken apart down the sink like cotton swabs, dental floss or hair clumps. These things usually get caught in the bend and immediately begin to cause problems.

  1. Piping slope issues

Plumbing is an angles game. For a drain to run effectively, the pipes need to be angled in a way that the water carries the waste through the plumbing. If the pipes are installed with too much slope, it can cause the water to run to fast and leave the waste behind. Over time, this remaining residue builds up, eventually causing a blockage.

  1. Pipe venting issues

Venting allows air to enter the pipe as the water drains, ensuring gases don’t build up to dangerous levels in your plumbing and to help the water drain. Poorly installed or blocked venting can cause the water to drain slowly.


Diagnosing the problem

Unfortunately, it’s quite difficult to diagnose the cause of a blocked drain without assistance for a plumber. However, you don’t necessarily need to be able to identify the type of blockage in order to fix it. We suggest trying a range of methods, starting with simple solutions (like hot water and salt) designed to fix the most common types of blocks and graduating upwards until you find something that works.



Using the baking soda and vinegar method is a waste of time

The baking soda and vinegar method has long been touted as drain plumbing cure-alls and whilst it won’t do anything to damage your plumbing, it’s unlikely to do anything to clear the blockage either. As most drain blockages are caused by a combination of fat and detritus build-up, they require a degreaser to be removed. Vinegar and baking soda is not an effective degreasing method, as when the acid and the base are combined, the chemical reaction only produces water and a very small amount of salt, neither of which have degreasing properties.


Step one: Try hot water

Pouring hot water (but not boiling) down the drain is a fantastic way to soften congealed fat and the addition of either salt or detergent can be used to help remove it entirely.

Hot water and detergent

This degreasing method is great for kitchen fat clogs. All you need to do is add detergent to hot water just below boiling and slowly pour it down the sink before following up with hot tap water. The hot water should act to soften the grease whilst the detergent will work to dissolve the fat and carry away the grime. This method usually needs to be repeated a few times to achieve the desired result


Hot water and salt  

The hot water plays a similar role in this method as it softens the fat. The salt is used as a scouring agent to dislodge greasy build-up. First, you’ll need to pour half a cup of cooking salt (coarse salt is ideal). Next, heat 2 litres of water until it is just below boiling and slowly pour it down the sink then follow with hot tap water. This method may also need to be repeated a few times before results are noticeable.

Step 2: See if you can physically remove the blockage from the top of the drain

If the hot water method isn’t working, your blockage may be too dense and consist of more debris than fat or grease. In this situation, physical removal is the best option. This can be achieved with a plunger, a straightened-out coat hanger with the end bent up in a hook, or a drain cleaning tool.

Step 3: See if you can physically remove the blockage from the elbow joint of the drain

This is not a particularly complicated procedure but it can get messy. Most blockages occur in the elbow pipe of a sink so simply unscrewing this part of the plumbing (if it is readily accessible) will make it much easier to clear away the gunk.

Step 4: Call a plumber

If you’ve tried all these methods, and are still struggling with a slow drain, call a plumber. You may still have a blockage problem, but it could be further down the plumbing line or be a sign of something more serious. Either way you’ll need expert skills and tools to fix it so give your local plumber a call.


JPG Plumbing are dedicated to help the people of Melbourne manage all sorts of plumbing problems from blocked drains through to commercial plumbing installations and emergency plumbing callouts. To learn more about our capabilities, please call us on 0400 978 442.