Following the road collapse accident in Yashio City, Saitama Prefecture, on January 28, 2025, believed to be caused by damage to a sewer pipe, the aging of sewer pipes and the importance of preventive maintenance are once again drawing attention. According to the Ministry of Land, Infrastructure, Transport and Tourism, as of the end of fiscal year 2023, there are approximately 500,000 km of sewer pipes nationwide (excluding urban waterways). Approximately 40,000 km (about 7%) exceed the standard service life of 50 years, and this is expected to increase to about 210,000 km (about 42%) in 20 years. Approximately 2,600 road collapses attributed to pipes occurred in fiscal year 2022 (*1), and emergency inspections and nationwide special priority surveys are being conducted following these accidents. On the other hand, a decrease in usage fees, an increase in renewal costs, and a shortage of technical staff are creating challenges in systematically and promptly repairing and renewing identified areas requiring countermeasures.

Against this backdrop, Seisui Kogyo Co., Ltd. (Head Office: Chiba City, Wakaba Ward, President: Kenichi Imoto, hereinafter "Seisui Kogyo", https://seisui-kk.com), an expert in water and sludge treatment, has conducted a survey on the actual state of the inspection and repair gap in municipal sewage systems targeting 108 employees involved in sewage projects in municipalities nationwide. We are pleased to announce the results.

*1 Ministry of Land, Infrastructure, Transport and Tourism "Water and Sewerage: Sewerage Maintenance (Promotion of Stock Management)", and "Fiscal Year 2023 Sewerage Pipe Maintenance Annual Report" https://www.mlit.go.jp/mizukokudo/sewerage/crd_sewerage_tk_000135.html

01 | Over 70% of municipal employees have experienced delays in starting repairs or postponed them even after they were determined to be "in need of repair."

02 | Challenges towards mandatory inspections are "securing budget" (52.8%) and "labor shortage" (50.9%) at the top.

03 | The process that takes the most time in the decision-making process is "consideration of temporary water treatment (bypass, etc.)" at 43.5%.

Download this survey here.

Survey Overview

Survey Name: Actual State Survey of Inspection and Repair Gaps in Municipal Sewage Systems

Survey Method: Internet survey conducted as planned by "Resapi®︎", a research marketing service provided by IDEATECH.

Survey Period: June 4, 2026 - June 5, 2026

Valid Responses: 108 employees involved in sewage projects in municipalities nationwide.

*The sum of percentages may not equal 100 due to rounding of the second decimal place.

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Approximately 70% of municipal employees are proceeding with inspection and preventive maintenance "according to plan" or "mostly according to plan," while over 20% recognize delays.

When asked, "Q1. In your municipality, are the "inspections and preventive maintenance" of the sewage infrastructure (pipes, treatment plants, etc.) under your jurisdiction proceeding according to plan?" (n=108), 25.0% responded "proceeding according to plan," and 44.4% responded "mostly proceeding according to plan."

Proceeding according to plan: 25.0%

Mostly proceeding according to plan: 44.4%

Somewhat not proceeding according to plan: 13.0%

Not proceeding according to plan at all: 8.3%

Don't know/Cannot answer: 9.3%

The top three barriers to mandatory inspections are "securing budget" (52.8%), "labor shortage" (50.9%), and "prioritization" (48.1%) for municipal employees.

When asked, "Q2. With the mandatory implementation of inspections, please list all challenges you anticipate in proceeding with "inspections and preventive maintenance" in the future. (Multiple answers allowed)" (n=108), the responses were "Difficult to secure budget for preventive maintenance" (52.8%), "Shortage of municipal employees (labor) to supervise inspections and construction" (50.9%), and "Difficult to diagnose collapse risk and prioritize repairs" (48.1%).

Difficult to secure budget for preventive maintenance: 52.8%

Shortage of municipal employees (labor) to supervise inspections and construction: 50.9%

Difficult to diagnose collapse risk and prioritize repairs: 48.1%

Difficult to secure temporary water treatment (bypass, etc.) during inspection/construction: 28.7%

Difficult to secure survey companies or construction contractors for outsourcing: 28.7%

Difficult to communicate with residents and coordinate restrictions on sewage use: 17.6%

Other: 0.0%

No particular challenges: 0.0%

Don't know/Cannot answer: 5.6%

More than half of municipal employees responded that they can secure "less than 70% of the required annual budget" for inspection and preventive maintenance.

When asked, "Q3. In your municipality, what percentage of the "annual budget" required for inspection and preventive maintenance of sewage infrastructure is secured compared to the amount considered necessary by the field?" (n=108), 38.9% responded "about half of the required amount is secured (50% or more, less than 70%)," and 23.1% responded "most of the required amount is secured (70% or more, less than 90%)."

Almost all of the required amount is secured (90% or more): 12.0%

Most of the required amount is secured (70% or more, less than 90%): 23.1%

About half of the required amount is secured (50% or more, less than 70%): 38.9%

Less than half of the required amount is secured (30% or more, less than 50%): 8.3%

Significantly insufficient compared to the required amount (less than 30%): 6.5%

Cannot calculate the required amount: 1.9%

Don't know/Cannot answer: 9.3%

71.3% of municipal employees have experience of not being able to start repairs or significantly postponing them after they were determined to be "in need of repair."

When asked, "Q4. In your municipality, have there been instances where repairs determined to be "in need of repair" based on inspection results could not be started (or were significantly postponed)?" (n=108), 21.3% responded "frequently," and 50.0% responded "occasionally."

Frequently: 21.3%

Occasionally: 50.0%

Rarely: 15.7%

Never: 3.7%

Don't know/Cannot answer: 9.3%

Problems experienced by municipal employees due to "inability to stop sewage flow" include "restrictions on resident use" (38.0%) and "trouble and cost of temporary water treatment" (35.2%) at the top.

When asked, "Q5. In past inspections and repairs of sewage infrastructure, what kind of problems have you experienced due to "inability to stop or bypass sewage flow"? (Multiple answers allowed)" (n=108), 38.0% responded "had to ask residents to restrict sewage use," 35.2% responded "design and arrangement of temporary water treatment required more effort and cost than expected," and 25.9% responded "repairs were postponed because bypass was not possible."

Had to ask residents to restrict sewage use: 38.0%

Design and arrangement of temporary water treatment required more effort and cost than expected: 35.2%

Repairs were postponed because bypass was not possible: 25.9%

Construction period was significantly extended: 24.1%

Risk of deterioration of treated water quality or overflow during construction: 20.4%

Construction contractors refused to accept the job or showed reluctance: 11.1%

Other: 0.0%

No particular experience: 12.0%

Don't know/Cannot answer: 6.5%

34.1% of municipal employees feel "there are limits to our own resources," and 26.1% feel "there are structural problems."

When asked, "Q6. To those who answered anything other than "No particular experience" or "Don't know/Cannot answer" in Q5. Please choose the one thing you felt most strongly through your experience." (n=88), 34.1% responded "felt there are limits to our own resources," and 26.1% responded "felt there are structural problems that prevent repairs from proceeding as planned."

Felt there are limits to our own resources: 34.1%

Felt there are structural problems that prevent repairs from proceeding as planned: 26.1%

Felt there is a need for more specialized contractors capable of temporary water treatment: 13.6%

Felt the need for technology and systems to minimize impact on residents and businesses: 12.5%

Felt the need to secure reliable partners in advance for emergencies: 5.7%

Other: 1.1%

Did not feel any particular strong points: 4.5%

Don't know/Cannot answer: 2.3%

Processes that take time in decision-making for preventive maintenance: 1st place is "consideration of temporary water treatment (bypass, etc.) methods and contractors," 2nd place is "budgeting and preparation of explanation materials for the assembly."

When asked, "Q7. In your municipality, which processes in the decision-making process for preventive maintenance based on inspection results do you find particularly time-consuming or difficult? (Multiple answers allowed)" (n=108), 43.5% responded "consideration of temporary water treatment (bypass, etc.) methods and contractors," 39.8% responded "budgeting and preparation of explanation materials for the assembly," and 38.0% responded "selection of repair methods (excavation, rehabilitation, etc.)."

Consideration of temporary water treatment (bypass, etc.) methods and contractors: 43.5%

Budgeting and preparation of explanation materials for the assembly: 39.8%

Selection of repair methods (excavation, rehabilitation, etc.): 38.0%

Judgment and consensus building for repair prioritization: 33.3%

Selection of outsourcing contractors and bidding procedures: 25.9%

Evaluation and coordination of impact on residents and surrounding businesses: 19.4%

Consultation and approval procedures with national government and related organizations: 13.0%

Other: 0.0%

No processes are particularly time-consuming: 1.9%

Don't know/Cannot answer: 8.3%

Over 70% of municipal employees were aware of "temporary water treatment" before discussions on mandatory inspections, with less than 20% having "detailed knowledge."

When asked, "Q8. Regarding the "temporary water treatment (including temporary bypass treatment, bypass, etc.)" method/technology, were you aware of it before hearing discussions about mandatory inspections?" (n=97), 19.6% responded "had detailed knowledge," and 51.5% responded "had some knowledge."

Had detailed knowledge: 19.6%

Had some knowledge: 51.5%

Only heard the name: 21.6%

Was not aware at all: 6.2%

Don't know/Cannot answer: 1.0%

When response is delayed or repairs are postponed, the risk municipal employees are concerned about is "restrictions on resident use" at about half.

When asked, "Q9. If response to "inspections and preventive maintenance" due to legal amendments is delayed, or if repairs are postponed due to limitations in temporary water treatment, what risks do you foresee for the local community and environment? (Multiple answers allowed)" (n=108), 49.1% responded "restrictions on resident use due to suspension of sewage treatment functions," 43.5% responded "environmental pollution of rivers and seas due to discharge of untreated sewage," and 37.0% responded "serious traffic accidents due to road collapse and paralysis of urban infrastructure."

Restrictions on resident use due to suspension of sewage treatment functions: 49.1%

Environmental pollution of rivers and seas due to discharge of untreated sewage: 43.5%

Serious traffic accidents due to road collapse and paralysis of urban infrastructure: 37.0%

Generation of odors and deterioration of public health: 34.3%

Expansion of flood damage during natural disasters such as torrential rains and typhoons: 34.3%

Enormous emergency response costs for recovery in case of accidents: 22.2%

Other: 0.0%

No particular risks foreseen: 1.9%

Don't know/Cannot answer: 3.7%

Themes municipal employees want to obtain information on in the future: "methods for repairing without stopping sewage flow" and "specialized contractors for temporary water treatment" are both at the top at 36.1%.

When asked, "Q10. In proceeding with measures for mandatory inspections, what themes do you particularly want to "obtain information on" or "learn about case studies" in the future? (Up to 3 answers allowed)" (n=108), 36.1% responded "case studies of methods and technologies for repairing without stopping sewage flow," 36.1% responded "information on specialized contractors capable of temporary water treatment (temporary bypass treatment)," and 33.3% responded "advanced cases of inspection and preventive maintenance in other municipalities."

Case studies of methods and technologies for repairing without stopping sewage flow: 36.1%

Information on specialized contractors capable of temporary water treatment (temporary bypass treatment): 36.1%

Advanced cases of inspection and preventive maintenance in other municipalities: 33.3%

Subsidy and grant systems usable between national and local governments: 31.5%

Criteria for determining repair priorities based on inspection results: 28.7%

Know-how for resident notification and coordination of usage restrictions: 10.2%

Selection criteria for outsourcing contractors and standard specification templates: 9.3%

Cost benchmarks and budgeting know-how for repair work: 5.6%

Other: 0.0%

None in particular: 3.7%

Don't know/Cannot answer: 4.6%

Summary

This time, we conducted an actual state survey of the inspection and repair gap in municipal sewage systems targeting 108 employees involved in sewage projects in municipalities nationwide. The results revealed that 71.3% of employees have experienced not being able to start or postponing repairs after they were determined to be "in need of repair," and that "securing budget" and "labor shortage" are challenges for over half of respondents in preparation for mandatory inspections.

First, 69.4% of employees reported that inspections and preventive maintenance are proceeding "according to plan" or "mostly according to plan." On the other hand, the combined response of "frequently" and "occasionally" for not being able to start or postponing repairs after being determined to be "in need of repair" reached 71.3%. Furthermore, challenges towards mandatory inspections include "difficulty in securing budget" (52.8%), "labor shortage" (50.9%), and "difficulty in prioritization" (48.1%), with over half of municipalities (53.7%) securing less than 70% of the required annual budget. Additionally, problems caused by the "inability to stop sewage flow" include "restrictions on resident use" (38.0%) and "trouble and cost of temporary water treatment" (35.2%), with "consideration of temporary water treatment" (43.5%) being the process that takes the most time for decision-making. Finally, the themes for which information is desired in the future are "case studies of methods and technologies for repairing without stopping sewage flow" and "information on specialized contractors for temporary water treatment," both at 36.1%.

This survey highlights the reality that while many municipalities are making progress with inspections to some extent, serious bottlenecks are occurring at the stage of translating those results into actual repairs. The background includes shortages in budget, labor, and technical expertise, and among these, the physical constraint of "inability to stop sewage flow" is considered to be structurally causing repair postponements. Now that the mechanism for "finding" problems is being established with mandatory inspections, the question is how to build a system for "fixing" them and how to collaborate with specialized technologies and contractors, including temporary water treatment.

Download this survey here.

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Solves with temporary water treatment plants using rental water treatment equipment with an abundant track record of 2,650 projects nationwide.

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Company Profile

Company Name: Seisui Kogyo Co., Ltd.

Established: April 1974

Representative Director: Kenichi Imoto

Location: Chiba Research Park, 424-18 Kamimizumi-cho, Wakaba-ku, Chiba City, Chiba Prefecture

Business Activities:

Planning for wastewater and sludge treatment

Rental of wastewater and sludge treatment plants

Rental of decanter centrifuges

Rental of various water treatment equipment

[NETIS] Civil Engineering Muddy Water Recycling System (Disaster Response)

[NETIS] Contaminated Soil Classification System (Disaster Response)

IHI Corporation Business Partner

URL: https://seisui-kk.com

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  • Source: PR TIMES
  • Category: Survey結果
  • Organizations: IDEATECH