Flood-prone land: how to know before buying and what to do if you already own it

Direct answer: yes, it is perfectly possible to know if a piece of land is prone to flooding before buying it. The three essential steps are: requesting the Prior Information Certificate (CIP) at the Municipal Works Directorate, checking the current regulatory plan, and conducting a technical review on-site. In rural areas without a regulatory plan, this technical and topographical review is your only real protection against future contingencies.

The recent storms that affected the central-south zone of our country have brought an urgent question to the table: can flood risk be foreseen? Beyond the context of the emergency, knowing the urban and topographical situation of a property is a permanent necessity. Buying in a risk zone is not illegal, but it means assuming different rules and costs. In this architectural and legal guide, we explain how to obtain the information before signing.

Step by step to verify the land before buying

The main document in urban areas is the Prior Information Certificate (CIP). This certificate is issued by the Municipal Works Directorate (DOM) and is the identity card of the land. It expressly states if the property is located in a "risk area" defined by the Territorial Planning Instrument. It is an inexpensive and public procedure; anyone can request the CIP on the official DOM online portal or in person with the Internal Revenue Service (SII) tax roll number.

Our main legal advice is never to sign a definitive purchase agreement without having reviewed the CIP. The correct approach is to sign a promise of sale agreement and include a clause that conditions the business on the CIP not showing unacceptable risk areas or, if it does, allows renegotiating the price, mitigating the financial risk. If you need professional support at this stage, our title study team can advise you on the safe drafting of the promise. Also, to prevent other issues, check our guide on how to avoid real estate scams in Chile.

What it legally means to buy in a "risk area"

The fact that a CIP indicates a flood risk zone does not prohibit construction, but it strongly conditions it. Article 2.1.17 of the General Ordinance of Urbanism and Constructions (OGUC) is exhaustive: to build in these areas, the owner must submit a "founded study" prepared by a specialist professional to the DOM, in addition to the engineering project of the necessary mitigation works.

In practical terms, this means that building permits will be conditional on the execution and reception of costly works (such as retaining walls or deep drains). Additionally, properties in official risk areas often face considerably higher insurance premiums, coverage exclusions for waterlogging, and eventually, a lower resale value in the real estate market.

The rural case: land without a regulatory plan

The greatest danger lies in rural areas. Communal regulatory plans rarely cover extensive rural areas, so the CIP will not warn of official risk areas. This is where the technical on-site review takes absolute prominence. The lack of normative mapping means that the real topography, the history of local floods, the memory of neighbors, and the proximity to streams or ravines are the only reliable indicators.

Before investing, a topographical survey with a runoff profile allows modeling how water will behave on the property during heavy rains, detecting hidden depressions under weeds or unstable fill zones. Our topography and architecture department specializes in these pre-purchase surveys, essential to avoid unpleasant surprises in winter.

If you are already an owner: your five options

If you already own a house or land that floods, there are legal and technical paths to follow in a logical order:

1. Inform yourself formally: request your CIP today. Confirm if the risk is regulated in the regulatory plan or if it responds to a purely geographical vulnerability.
2. Mitigate: in rural areas, keep the canals and inner watercourses of your property clean. On urban properties, hire the design of formal mitigation works.
3. Insure: carefully review your property's insurance policy. Check if it has specific clauses against earthquakes and floods or overflows.
4. Regularize: if you expanded your property as an emergency, find out the legal ways to regularize.
5. Sell with transparency: if you decide to sell, you must inform the buyer. Hiding that the land floods severely every winter can constitute "redhibitory" or hidden defects, according to the Civil Code, granting the buyer legal actions to annul the contract or demand a proportional reduction of the price paid.

Reconstruction after the storm and the law

Following the storm that devastated the country, many owners face reconstruction. There is a dilemma: process the building permit from scratch including mitigation works (slow way, but definitive), or rebuild due to emergency and regularize later relying on exceptional regulations like Law 20.892 (see our article on the Monkey Law).

Additionally, a mega-reform is being processed in Congress that includes transitory tax exemptions for reactivation, aiming to facilitate new housing (you can learn more in our article about the VAT mega-reform), which could indirectly alleviate the housing supply for affected families in Biobío and Ñuble.

Checklist: what to review before buying

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