Groundwater Utilization in Osaka Prefecture -Prefecture Database-

Overview of groundwater and groundwater heat utilization in Osaka Prefecture

When promoting the utilization of groundwater and groundwater heat, the most important thing is the availability of groundwater.
This page summarizes the groundwater situation in Osaka Prefecture and useful groundwater-related websites.

*This information is current as of January 2019. Please check the latest information when making your decision.

Image: Overview of the Osaka Prefecture Restricted Area (from the Osaka Prefecture website)

Ordinances on groundwater utilization

The first information you should check is each local government's ordinance regarding groundwater pumping.
When using groundwater, you must submit a notification and comply with regulations regarding the amount of groundwater to be collected and the diameter of the well, etc., in accordance with this ordinance.

In Osaka Prefecture, regulations are mainly based on the following laws and ordinances.

① Industrial Water Law
② Law Concerning the Regulation of Groundwater Extraction from Buildings (Building Water Law)
③Osaka Prefecture Ordinance on Preservation of Living Environment
④ Municipal ordinances (Hirakata City, Higashiosaka City, Daito City, Settsu City, Shimamoto Town)

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<Well conditions subject to regulation> ①～③ Common
Wells with pump outlet diameter of 6cm2 or more (effectively 32A or more)
(For areas regulated by prefectural ordinances, this is the total for wells on the premises, excluding manual pumps.)
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Image: Overview of the Osaka Prefecture Restricted Area (from the Osaka Prefecture website)

Regulations within Osaka Prefecture are divided into even smaller units than the city or town level, making them more complex.
If you are unable to make an accurate judgment from the image above, please check the following page to confirm which regulatory zone your area falls into.

Osaka Prefecture Groundwater Extraction Restriction Area Map:http://www.pref.osaka.lg.jp/kankyohozen/jiban/saisyuryou.html

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In areas regulated by the Industrial Water Law, Building Water Law, and Prefectural Ordinance, water utilities are required to not only limit the pump discharge diameter, but also to make well strainers 100 to 600 meters or more deep depending on the area, making it difficult to use groundwater at a reasonable price.
If the above applies to you, you will need to choose between a small diameter well with a discharge diameter of 6cm2 or less, or a deep well that meets the regulations.

Prefectural ordinances do not regulate the diameter or depth of wells when they are used for purposes other than water supply services, but there is an obligation to report the amount of water pumped to the prefectural governor.

In areas that do not fall under any of the above categories and where there are no municipal ordinances, groundwater can be used without regulation within appropriate limits.

Regulations by regulatory domain:http://www.pref.osaka.lg.jp/kankyohozen/jiban/kiseikuiki.html

Please see the link below for information on city or town ordinances in ④.
Even in other cities and towns, we recommend that you check with your local government office before making any plans.

Hirakata City:https://www.city.hirakata.osaka.jp/cmsfiles/contents/0000004/4372/80032.pdf
Higashiosaka City:http://www.city.higashiosaka.lg.jp/0000000764.html
Settsu City:http://www.city.settsu.osaka.jp/sangyou/kankyou/machidukuri/kankyouhozen/4667.html
Shimamoto Town:http://www1.g-reiki.net/shimamotocho/reiki_honbun/f800RG00000265.html?id=j12

Ordinances and regulations regarding wastewater utilization

● Water quality standards for discharged water
When discharging groundwater used in a factory or business into a drain, river, etc., it is necessary to comply with the water quality standards set out in the Water Pollution Control Act.
Osaka Prefecture also sets standards in the Seto Inland Sea Environment Conservation Special Measures Act and the Osaka Prefecture Ordinance on the Conservation of Living Environment, etc.
It is rare for groundwater itself to exceed the standard values, but there are cases where pollutants from soil contamination have flowed in, so it is necessary to check in advance.
When groundwater contamination is confirmed in each local government, the data is made public.

●Discharge into the sewer system and sewerage fees
When used groundwater is discharged into the sewer system, a sewerage fee is charged according to the amount discharged.
When groundwater is used as drinking water, sewerage charges are generally determined based on the water intake meter.
However, if groundwater used as a heat source is discharged into a drain or river, it is often possible to have it not counted in sewerage charges by checking with the local government in advance.

●Other
Depending on the region, associations and other groups may have their own rules.
Please be careful if this affects agricultural associations, hot spring associations, industrial complexes, etc.

Osaka Prefecture Water Quality Regulations:http://www.pref.osaka.lg.jp/jigyoshoshido/mizu/index.html

Groundwater Resources

Osaka Prefecture has been actively utilizing groundwater for industrial use, taking advantage of the abundant groundwater that accumulates in the Osaka Plain.
However, excessive pumping during the period of high economic growth caused land subsidence, so in addition to the strict regulations mentioned above, local governments have also begun to monitor the area.
Although land subsidence is currently showing signs of slowing down, when using groundwater, it is necessary to comply with laws and regulations and to design wells that take into account the risk of subsidence.
As an area extremely rich in water resources, with proper planning, groundwater utilization can be effective.

Water quality and depth vary from region to region, and while some areas have water suitable for drinking, coastal areas tend to be salty and some areas have detectable ammonia, so there are unique conditions. It is necessary to have an expert check beforehand.