[Edaily Reporter KIM HYUNG-HWAN ] A recent investigation found that despite nearly 700 billion won in public funds having been spent over the past six years on “permeable blocks”—installed on sidewalks to reduce flooding—the process for conducting post-installation performance inspections has been inadequate. Calls are growing for the Ministry of Land, Infrastructure and Transport and local governments to take responsibility for ensuring that these funds are used effectively.

According to data submitted on the 14th by the Ministry of Land, Infrastructure and Transport and the Public Procurement Service to Rep. Jeon Yong-gi of the Democratic Party of Korea, a member of the National Assembly’s Land, Infrastructure and Transport Committee, the total contract value for permeable blocks in the public sector from 2021 through August of this year amounted to 695.025 billion won. By year, the figures are as follows: △110.6 billion won in 2021, △124.9 billion won in 2022, △137.7 billion won in 2023, △124.3 billion won in 2024, △115.7 billion won in 2025, and △81.8 billion won from January to August 2026.

Permeable pavers are sidewalk blocks designed to allow rainwater to seep into the ground; unlike standard sidewalk blocks, they feature microscopic gaps that prevent rainwater from pooling and allow it to pass through to the ground below. With a recent spate of flooding damage caused by extreme weather, the importance of permeable pavers is being increasingly emphasized. In South Korea, the Ministry of Land, Infrastructure and Transport’s “Guidelines for Sidewalk Installation and Management” stipulate that the permeability coefficient must be at least 0.1 mm per second.

However, there is no procedure in place to verify whether water drains properly after the product has been installed on-site. According to current guidelines, there is no obligation to measure on-site permeability during the final inspection, nor is there an obligation to continuously remeasure performance after completion.

In fact, the performance of permeable blocks varies significantly depending on post-construction maintenance. According to the “Study on the Long-Term Permeability Performance of Permeable Pavement in Urban Areas of Seoul,” published in the international academic journal “Water Science and Technology,” a study titled “Long-Term Permeability Performance of Permeable Pavements in Urban Areas of Seoul” surveyed 13 sections of permeable blocks installed in Seoul from May 2018 to June 2021. The results showed that 8 of these sections (61.5%) failed to meet the recommended permeability standards at the conclusion of the survey. Although all 13 sites had permeability performance rated at Grade 1 or 2 at the start of the survey, by the end of the survey, 5 had dropped to Grade 3, and the remaining 8 had fallen to the lowest grade, Grade 5.

Furthermore, the rate of inspections conducted by specialized agencies at the product stage has remained in the 1% range annually over the past six years. For the majority of the remaining cases, the requesting agencies conduct the delivery inspections themselves.

In response, some local governments have launched their own inspections, but the results have not yet been made public. The Seoul Metropolitan Government plans to conduct an assessment and analysis of the permeability performance of permeable blocks from last May through this November. In addition, starting last year, it introduced “on-site permeability performance evaluations” to verify the permeability of permeable blocks upon project completion.

Councilman Jeon Yong-gi stated, “In a situation where urban flooding damage recurs every year due to torrential rains, investing a budget of nearly 700 billion won to prevent flooding while failing to even verify whether the water is draining properly is a classic example of ‘showpiece’ administration,” adding “Since the installation of permeable blocks is not an end in itself—the key is actually reducing flood damage—the government must establish standards for post-construction performance verification and follow-up management to ensure public safety and prevent the waste of taxpayer money,” he emphasized.