Hello, this is Attorney Bae Ki-hyung of Cheongchul Law Firm.

In the large-scale defect repair cost lawsuits that apartment residents' councils have recently been filing against developers and contractors, certain special items have become new battlegrounds alongside the traditional concrete cracks and finishing defects. The most prominent are 'sprinkler pipe leaks' and 'dead landscape trees' within the complex.

With these two types of defects, it is very difficult to draw a clean line on who is responsible: whether the cause is the contractor's fault (a construction defect), a flaw in the original design (a design defect), or poor management by the residents (neglected maintenance). Moreover, once a defect is recognized, full replacement or replanting costs anywhere from hundreds of millions to billions of won, so the two sides clash fiercely over appraisal results and legal doctrine during litigation.

Today we look at how the courts and practitioners allocate responsibility for sprinkler leaks and dead landscape trees, which have emerged as key issues in recent apartment defect litigation.

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[Question] If a sprinkler pipe leaks or landscape trees in the complex die, can the contractor automatically be treated as having built them defectively and be billed for the full cost of reconstruction?

[Answer] In short, not necessarily. Given the nature of mechanical systems and landscaping, depending on the case the cause may be found to be a 'design defect' or 'neglected maintenance by the residents' rather than the contractor's fault, in which case the contractor's liability may be denied or the damages substantially reduced.

1. Sprinkler Leaks: Design Defect or Construction Defect?

In the past, apartment projects commissioned by public agencies such as LH and SH typically used seamless copper pipe (KS D 5301) for wet-pipe sprinkler systems. However, because sprinkler pipes hold stagnant rather than flowing water, crevice corrosion from oxide deposits or differences in oxygen concentration frequently caused tiny holes to form in the pipes, the so-called 'pitting corrosion (孔蝕)', leading to large-scale leaks.

The residents or the project owner then argue that "foreign matter entered the pipes during construction and accelerated the corrosion, so this is a construction defect and the pipes must be fully replaced." The contractor counters that "copper pipe is itself unsuitable for a stagnant-water environment, yet the owner specified its use, so this is the owner's 'design defect' and the contractor bears no responsibility."

On this issue, the prevailing trend in recent lower court decisions is to treat such leaks in principle as a 'design defect' (see, e.g., Seoul High Court Decision 2021Na2042932, December 8, 2023). In other words, if the contractor built the system properly in accordance with the owner's design drawings and specifications (which directed the use of copper pipe), the contractor cannot readily be held liable for the defect unless a specific construction fault, such as introducing foreign matter during construction, is concretely proven. In addition, where leaks occurred only locally in some units, courts in practice limit the scope of repair, finding it excessive to calculate the cost of replacing the pipes in every unit.

2. Dead Landscape Trees: Poor Workmanship or Neglected Maintenance?

The death of landscape trees within apartment complexes is another staple issue in litigation. Under the Standards for Defect Inspection, Repair Cost Calculation and Defect Determination in Multi-Family Housing (공동주택 하자의 조사, 보수비용 산정 방법 및 하자판정기준), a notice of the Ministry of Land, Infrastructure and Transport, a tree is deemed dead (枯死) and treated as a construction defect if two-thirds or more of the branches in its crown (the part with branches and leaves) have died, or if its growth is so poor that recovery is deemed unlikely, and the replanting cost is to be calculated based on the tree specifications in the design documents.

However, because landscaping deals with living plants, trees very often die even when the contractor planted them properly to specification, due to pests and disease, abnormal weather, or 'neglected maintenance' such as inadequate watering by the residents' council (management office) after move-in.

Accordingly, where landscape trees die within the defect warranty period, most lower courts recognize this prima facie as the contractor's defect and calculate replanting costs, but then broadly apply the 'limitation of liability (reduction) doctrine' under the principle of good faith, taking into account the nature of trees as living organisms and the residents' own maintenance responsibilities (see, e.g., Seoul Central District Court Decision 2018GaHap582116, October 21, 2020). Furthermore, whether replacement or additional planting that the contractor has already carried out at the residents' request should be deducted from the defect repair cost is another hotly contested point in litigation.

Identifying the Cause and Allocating the Burden of Proof Decides the Case

In practice, in these special defect lawsuits the contractor's liability cannot be established merely from the result that "water is leaking" or "trees have died." What matters is to meticulously identify the root cause, whether a design error, poor workmanship, or neglected maintenance, through highly specialized construction appraisal.

From the plaintiff's side (the residents' council or project owner), only by collecting samples from the leak site and proving a clear construction fault such as the intrusion of foreign matter can one secure compensation approaching full reconstruction. Conversely, the defendant (contractor) should adopt a defense strategy of actively presenting its compliance with the design documents, the characteristics of the water quality, and evidence of the residents' poor maintenance (such as tree maintenance logs) in order to cut down unjustifiably inflated repair cost claims running into billions of won.

Disputes over mechanical system and landscaping defects are an area where complex engineering causation and legal allocation of responsibility intersect, so a concrete legal review is needed from the earliest stage of the dispute.

Cheongchul Law Firm provides optimal solutions to prevent unjust losses and protect our clients' legitimate rights, based on a deep understanding of large-scale multi-family housing defect disputes and construction appraisal practice. If you are struggling with difficult defect issues such as sprinkler leaks or dead landscape trees, please consult the experts at Cheongchul Law Firm.

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Attorney Bae Ki-hyung has worked at the Defense Installations Agency and in the construction and real estate team of a major law firm, providing legal advice on every stage of government contracts and construction projects, including large-scale construction works such as public works, defense facility projects and SOC construction projects, and has extensive experience and proven skill in resolving related disputes. If you need assistance with public works, private construction projects, public procurement contracts, state property, local government property or public property, please feel free to contact us at any time.

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Cheongchul Law Firm is composed exclusively of attorneys from Korea's five largest law firms, the Prosecutors' Office, and the legal teams of major corporations, and rather than relying on a single attorney, we form teams of attorneys specializing in the fields relevant to each case. Beyond resolving specific issues, Cheongchul provides comprehensive solutions for the business as a whole, offering legal consulting focused on ultimately achieving what our clients want. If you need help reaching your goals, please do not hesitate to contact Cheongchul.