Why you should check a property’s drainage diagram

hen you inspect a property, what precautions do you take to make sure you’re making the right investment?

Pest control? Foundation check? A full building inspection? These are all good places to start, but don’t forget to check the drainage diagram.

Don’t forget to check the drainage diagram.

Drainage diagrams should be lodged with the state’s water board and knowing how your drainage compares with your property’s layout could save you a lot of time and money in the future.

Read more: What is a drainage diagram?

What’s hidden below a fresh renovation?

Are you looking at a property that’s been recently renovated? A drainage diagram can be a looking glass into what a renovated façade could be hiding. It can be especially important if the drainage diagram pre-dates the renovation.

What does the diagram mean?

There are two common scenarios:

  1. Fixtures on the diagram are in the same place in the diagram as in real life.
  2. Fixtures are in a different position and don’t match the diagram.

1. Fixtures in the same place as in real life

What does this mean?
The renovator has chosen to upgrade the fixtures and use the existing pipework.

Best case scenario:

  • pipes are in good shape
  • renovation was done properly.

Read more: Hidden plumbing problems & how to uncover them

Worst-case scenario:

  • pipes are in bad condition and needed replacing but haven’t been and will probably leak at some point.

It’s important to point out here that you won’t know which scenario you have until you have an in-progress worst case.

If you get a plumber who is awesome at leak detection and has all the right gear, your loss may be a few to several hundred dollars, with possibly the change of a few tiles. Your absolute worst case scenario is a complete do-over of that renovation.

What to do?

  • Ask the real estate agent if renovations were carried out and by whom.
  • Find out if pipework behind the walls was updated or new fixtures were installed onto old pipes. When the pipework isn’t updated, the job is cosmetic and you have the equivalent of a shiny paint job on an old car whose engine may not be in good nick.
  • Find out if the bathroom was completely re-tiled and re-waterproofed.
  • Find out if the renovation was part of a DA and request compliance and inspection documentation.

Depending on the answers given, you could try to negotiate a price reduction or factor extra costs into your maximum house purchase budget.

Knowing the facts could help your negotiate the property’s sale price.

Read more: What to consider when renovating a bathroom

2. Fixtures don’t match the diagram

What does this mean?

It’s when fixtures indicated in a drainage diagram are in a different spot to what’s actually seen in reality.

Best case scenario: 

  • Plumber forgot to update the drainage diagrams.

Worst case scenario:

  • Either the plumber, or the unlicensed “plumber” (for example, the homeowner) or the two of them together decided to ignore regulations. In my book, this equals a can of worms. You have to ask yourself what other regulations or standards they decided to ignore.  

If a renovation has been carried out by an unexperienced homeowner it could equal a can of worms.

What to do?

  • Make it known that you’ve done your research and look at (and mention) the Office of Fair Trading to see what support you can get. An updated diagram should be forthcoming if it’s clear you know your rights. If it is and the diagram matches real life – great.

If the diagram doesn’t match:

  • Walk away and leave this set of problems to someone else.
  • If you can’t bring yourself to walk away, engage a builder, plumber/roofer and an electrician to complete thorough inspections.

At this stage it’s better to spend a few hundred to around a thousand dollars on inspections than to buy a lemon that you have to spend tens of thousands of dollars rectifying.

Spending a few hundred dollars on inspections is better than paying a few thousand dollars to fix a lemon.

Read more: 6 tips to build sweet foundations with your builder

Why the date matters

If the drainage diagram date is roughly around the time of the renovation, things are looking good, but beware the following scenarios:

  1. Fixtures are in a different position and don’t match the diagram
  2. Fixtures are in a different position but match the diagram.

1. Fixtures are in a different position and don’t match the diagram

What does this mean?

This would be odd because the plumber has gone to the trouble of submitting a new diagram to your state’s water authority. You at least know that a licensed plumber was working on the home at some point.

Best case scenario:

  • Check the stamps on the diagram as it could well be that the admin is just not complete and the pipework has been updated.

Worst case scenario:

  • This could be a warning sign that the repairs or renovations were either done by an unlicensed plumber or by a shoddy or lazy one.

What to do?

  • Make sure the agent knows about your concerns with the diagram and request an explanation. A drainage diagram should be forthcoming where everything matches.
  • If your building inspector or solicitor can’t draw any conclusions using the diagram when they inspect the property, bring in a professional plumber to look at the pipework and they’ll be able to answer all your questions.

2. Fixtures are in a different position but match the diagram

What does this mean?

  • When the renovation was done, the position of bath/basin/toilet was moved and required new pipework behind the wall – that’s a good sign. You’ve got a pretty reno on top and brand new pipes behind the wall.
  • You know the plumber follows regulations, submits his paperwork and that is always a great sign and a good beginning.

Remember this doesn’t guarantee a quality renovation but it does mean more extensive work was completed. You are way out in front of the people with the previous scenarios.

As a buyer, having an up-to-date drainage diagram can tell you a lot about a property’s renovation credentials and help you if you need professional plumbing assistance, so don’t discount this essential part of your due diligence.

It could mean a sound solid purchase or it could spell out a series of costly and painful repairs will soon rear their ugly head.