DIP & SIP: What Every Landed Property Buyer in Singapore Should Know
When buying a landed property in Singapore, most buyers naturally focus on the things they can see.
How big is the land? How many bedrooms are there? Is the house renovated? Is it near an MRT station? How much is the asking PSF? And perhaps most importantly, can the property eventually be rebuilt or extended into the home they want?
But there is another side of landed property that you cannot see simply by walking through the house.
What is underneath the land? What runs around the property? And are there any drainage or sewerage considerations that could affect future works?
This is where two documents become useful: the Drainage Interpretation Plan (DIP) and the Sewerage Information Plan (SIP).
These names may sound very technical, but the concept is actually quite straightforward. The DIP provides information on drainage reserves and land reserved for future drainage schemes, while the SIP shows the location and alignment of public sewers or pumping mains in the vicinity of a development.
For most people buying their first landed home, these are probably not documents you have encountered before. So in this article, I want to explain them in simple terms, why they matter, where you can get them and, most importantly, when you should actually bother getting one.
What Is a Drainage Interpretation Plan?
Let's start with the Drainage Interpretation Plan, or DIP.
In simple terms, the DIP gives you information about drainage reserves or land that has been reserved for future drainage schemes.
This becomes relevant because drainage infrastructure is part of Singapore's wider system for managing surface water. If you are buying a landed property with plans to carry out substantial additions or redevelopment, you need to know whether any drainage reserve or common drain could affect the way the site is developed.
DIP also provides information on the Minimum Platform Level (MPL) needed for effective surface-water drainage. However, there is an important limitation: details of common drains at a development may not be shown on the plan, so the relevant Qualified Person should verify the actual common drains on site.
Here’s what URA has advised on how the drainage reserve will affect the property:
For internal renovation within the existing house, repainting, reroofing works, where there is no encroachment into the drainage reserve, vesting of the drainage reserve is not required, provided the proposal complies with the A&A criteria. To clarify, the land has not been vested to the State at this point in time. Although it is safeguarded as drainage reserve, it is currently still under private land ownership.
The land affected by the drainage reserve is to be vested to the State. This will be required when there is a new erection/reconstruction proposal.
This is important because a buyer might see a large 3,000 or 4,000 sq ft plot and immediately think:
"There is plenty of land. I can rebuild whatever I want."
But the reality is that having a large plot does not automatically mean every part of the land can be used however you want.
The DIP is one of the documents that helps your architect or engineer understand the drainage-related constraints of the site before a development is designed.
What Is a Sewerage Information Plan?
The Sewerage Information Plan, or SIP, looks at a different part of the infrastructure.
The SIP indicates the location and alignment of public sewers or pumping mains in the vicinity of the development.
In layman's terms, you can think of it as helping answer a question like:
"Is there a public sewer or pumping main running near or through the area where I'm planning to build?"
This can become especially important for landed homeowners who are looking at major works such as rebuilding or substantial additions.
Under PUB's current Code of Practice on Sewerage and Sanitary Works, the SIP should be obtained before proceeding with development design, and the exact position, alignment and levels of affected sewers and pumping mains must subsequently be established on site. PUB's requirements also state that proposed development must comply with requirements relating to structures over sewers and required setback distances, unless the relevant PUB approvals are obtained.
Again, that doesn't mean:
"There is a sewer nearby, therefore you cannot build."
It means the sewerage infrastructure needs to be understood and properly incorporated into the design.
Using the above SIP as an example, with an existing sewer line running across the land. If you want to construct a building/structure over an existing public sewer, you need PUB's approval. Where the proposal cannot comply with the normal sewer setback, PUB may require an RC trench to protect the sewer.
Why Should a Landed Property Buyer Care About These Plans?
At first, you might be wondering why any of this should concern you. After all, you're buying a house, not designing the Singapore sewerage system.
The reason is simple: with landed property, the land itself is part of the value proposition.
A large proportion of the appeal of an older landed house may come from its future potential. Perhaps you like the location but don't like the existing house. Perhaps you are buying a 2-storey home intending to rebuild it. Perhaps the property has a large backyard and you are already imagining an extension. Or perhaps you are paying a premium because you believe you can create a much larger dream home on the existing plot.
In these situations, understanding the site becomes much more important.
Consider two landed properties with similar land sizes. One may have a relatively straightforward plot that works well with your architect's proposed design.
The other may have drainage or sewerage infrastructure that needs to be carefully accounted for.
On paper, they may both say 2,500 sq ft land. But that does not necessarily mean they offer exactly the same development potential. And this is one of the reasons I always encourage landed buyers to look beyond the headline land size and asking PSF.
You are buying the land, but you also need to understand the limitations around that land.
Does Having a Drainage Reserve Mean the Property Is a Bad Buy?
No.
This is worth emphasising because these plans can sound much more frightening than they actually are.
A property affected by a drainage reserve is not automatically a bad property.
The impact depends on the location, extent and characteristics of the reserve, the existing property and what you are actually trying to do with the house.
A homeowner who simply wants to repaint the house, renovate the kitchen and modernise the bathrooms is in a very different situation from a buyer who wants to completely demolish the existing property and construct a new house with a basement.
The same property could therefore be perfectly suitable for one buyer but require much more investigation for another. That is ultimately something your architect or other relevant Qualified Person needs to assess.
Where Can You Get the DIP and SIP?
The good news is that you don't need to go around looking for different government agencies and request paper plans individually.
PUB Service Plans can be obtained through SLA's INLIS platform.
INLIS is the Integrated Land Information Service operated by the Singapore Land Authority. For buyers, the simplest place to start is the official PUB page, which explains the different service plans and provides the link to INLIS.
You should also make sure that you are looking at the latest available information, rather than relying on an old plan that a previous homeowner, contractor or agent happens to have.
Who Actually Needs to Buy a DIP or SIP?
The honest answer is that not every landed buyer needs to rush out and buy both documents the moment they start viewing houses.
If you're buying a relatively new landed property, you are happy with the existing house and you have no plans for substantial construction, these plans may not be particularly important at the very beginning of your search.
The situation changes when the land itself is a major reason why you are buying the property. For example, if you are looking at an older landed house because you intend to rebuild, I would consider this part of your due diligence.
The same applies if you are considering substantial A&A works, a significant extension or a project involving a basement.
It is also worth investigating if an agent or seller is marketing a property heavily based on its so-called "redevelopment potential."
Whenever you hear statements like:
"Huge plot — great for rebuilding."
or:
"Lots of potential for extension."
I think it is reasonable to ask:
"Potential based on what?"
The land size is only the starting point. The actual development potential needs to be assessed against planning requirements, site constraints and the various infrastructure considerations affecting the property.
When Should You Get the DIP and SIP?
Personally, I would not recommend buying these plans for every landed property you casually view.
There is a more practical way to approach it.
During your initial property search, focus on the fundamentals: location, budget, land size, frontage, layout and whether you actually like the property.
Once you find a property that you are seriously considering, that's when deeper due diligence should begin, especially if your buying decision depends on what you can eventually do with the land.
For example, suppose you find an older 2-storey inter-terrace in Kovan that is priced attractively because the existing house is dated. You don't particularly care about the current renovation because your plan is to rebuild.
In that situation, I would want to understand the site before becoming overly committed to the assumption that you can build your dream house there.
The DIP and SIP form part of that investigation. You would then take the information to your architect or Qualified Person, who can assess it together with the actual site conditions and your intended development.
Don't Make the Mistake of Treating the Plan as the Final Answer
This is perhaps the most important point in the entire article. A DIP or SIP is not a building approval. It does not give you a simple green light saying:
"Yes, you can build three storeys."
Nor does it mean:
"No, you cannot renovate."
They are information plans that help professionals understand the infrastructure affecting a development.
PUB specifically states that Qualified Persons need to obtain the relevant information from PUB Services Plans and conduct site surveys to verify the alignments and levels of public sewers, pumping mains, sewer connections, drainage reserves and common drains.
PUB also highlights that some details may not appear on the plans. For example, existing sewer connections may not be shown on the SIP, while common drains may not be shown on the DIP. These therefore need to be verified on site.
So I would look at it this way:
The DIP tells you what drainage-related information you need to be aware of.
The SIP tells you what public sewerage infrastructure may affect the site.
Your architect or Qualified Person tells you what those things actually mean for your proposed project.
That is the distinction that buyers should understand.
So, Do You Really Need a DIP or SIP?
For someone buying a landed house strictly as a move-in-ready home, perhaps not immediately.
But for someone buying an older landed property because of the land, redevelopment potential or future A&A possibilities, I would absolutely want these issues investigated before assuming the property can be transformed in the way I imagine.
This is especially relevant in older landed estates, where you can have properties built many years apart, different plot configurations and various drainage and sewerage arrangements around individual sites.
And that's really the point.
When buying a condo, you are mostly evaluating the unit.
When buying landed property, you are evaluating the land, the house, and everything that may affect the land's future use.
The DIP and SIP are simply part of that bigger picture.
My Take as a Landed Property Agent
One of the biggest mistakes I see buyers make when looking at landed property is falling in love with the potential before checking whether that potential is actually realistic.
They see a large plot.
They imagine a brand-new three-storey home.
They calculate the potential built-up area in their heads.
Then they work backwards and decide how much they think the property is worth.
I think the order should be reversed.
Understand the land first.
Then understand the constraints.
Then speak to the right professionals.
Then work out what can realistically be done.
And only after that should you decide how much you are comfortable paying for the property.
The DIP and SIP may not be the most exciting documents you'll encounter when buying a landed home, but when you're spending several million dollars on a piece of land, the boring details can sometimes be the ones that matter most.
And that is especially true when the property you're buying isn't simply a house to live in today, but a piece of land that you hope to transform tomorrow.
Thinking of Buying or Selling a Landed Property in District 19?
If you are considering buying or selling a landed property in District 19, having the right market information can make a significant difference. I specialise in District 19 landed properties, including Kovan, Serangoon Gardens, Bartley, Hougang and the surrounding landed estates, and I regularly study transaction prices, PSF trends, land sizes, frontage, plot characteristics, property condition and redevelopment considerations.
Whether you are trying to understand how much your landed property is worth, whether an asking price is reasonable, or what to look out for when buying an older landed house, I am happy to have a 1-to-1 discussion with you and help you make your decision based on data, rather than assumptions.
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