Regulations for Groundwater Monitoring
Name of Act, Rules or Standards Article Article Content
Water Pollution Control Act Article 10

Competent authorities at all levels shall install water quality monitoring stations, perform sampling and testing work, issue official announcements of testing results at regular intervals and adopt appropriate measures.

An irrigation competent authority or a relevant agency may be commissioned to perform the water quality monitoring work in the foregoing paragraph.

Water Pollution Control Act Enforcement Rules Article 7

The water quality monitoring stations designated in Article 10, Paragraph 1 of this Act shall be installed and perform monitoring pursuant to the following regulations.

  • The central competent authority shall install monitoring stations depending on the water quality circumstances in surface water bodies and groundwater bodies involving two or more special municipalities, counties or cities.
  • Special municipality, county and city competent authorities shall install monitoring stations depending on the water quality circumstances in surface water bodies and groundwater bodies within their jurisdictions.


The sampling frequency of water quality monitoring stations in the foregoing paragraph shall, in principle, be once per quarter and these stations shall monitor the following items.

  • Water temperature
  • Hydrogen ion concentration index
  • Dissolved oxygen
  • Heavy metals
  • Other items designated by the central competent authority based on water body characteristics


Competent authorities at all levels shall issue official announcements for monitoring results and statistical data on a quarterly basis and special municipality, county and city competent authorities shall report data to the central competent authority to be filed for future reference.

Installation and Monitoring Standards of Water Quality Monitoring Stations Article 1 These Standards are established pursuant to Article 15, Paragraph 4 of the Enforcement Rules of the Water Pollution Control Act .
Article 5

Water quality monitoring stations for groundwater shall, in principle, be installed in the following locations:

  • major pollution sources;
  • seawater intrusion areas;
  • other areas with higher pollution potentials;
  • major water use points;
  • spots reflecting general water quality;and
  • other essential spots.
Article 9 The sampling frequency and procedures of groundwater shall conform to the following provisions:
  • The sampling frequency shall, in principle, be once per quarter. However, for areas with pollution risks, the frequency shall be raised.
  • Representative water samples shall be obtained while sampling.
Soil and Groundwater Pollution Remediation Act Article 5

Competent authorities of special municipalities, counties and cities (hereinafter referred to as local authorities) shall examine the quality conditions of soil and groundwater within their jurisdictions at regular intervals, take necessary measures if any pollutant reaches its control value, investigate who should be responsible for the pollution, and report to the central authority. If the concentrations of pollutants are lower than the control values designated in the Soil or Groundwater Pollution Control Standards and conform to the Soil or Groundwater Pollution Monitoring Standards, they shall be monitored at regular intervals. Furthermore, the monitoring results shall be officially announced and be reported to the central authority for future reference.

Groundwater Pollution Monitoring Standards Article 4 Monitoring items and standard values (concentration unit: mg/l) for pollutants are shown in Table 1.
Groundwater Pollution Control Standards Article 4 Pollutants and control values (concentration unit: mg/l) are shown in Table 2.
Drinking Water Source Quality Standards Article 5 The water quality of surface water and groundwater bodies that are used as drinking water sources (both tap and non-tap water) shall conform to the requirements listed in Table 3.
Irrigation Water Quality Standards   Relevant provisions of the Irrigation Water Quality Standards, published in Nong-Lin-Zi No. 0920031524 on November 7, 2003, are listed in Table 4.
Table 1 Pollutant Monitoring Items and Monitoring Standard Values(Concentration Unit: mg/l)
Pollutant Monitoring Item Monitoring Standard Value
Class A Class B
Heavy Metals
Arsenic(As) 0.025 0.25
Cadmium(Cd) 0.0025 0.025
Chromium(Cr) 0.025 0.25
Copper(Cu) 0.5 5
Lead(Pb) 0.025 0.25
Zinc(Zn) 2.5 25
Iron(Fe) 0.15 1.5
Manganese(Mn) 0.025 0.25
General Items
Total Hardness(CaCO3) 150 750
Total Dissolved Solids 250 1250
Chloride 125 625
Ammonia Nitrogen 0.05 0.25
Nitrate Nitrogen(Nitrate as N) 5 25
Sulfate(SO42- 125 625
Total Organic Carbon 2 10
Phenols 0.014 0.14
Table 2 Pollutants and Control Values (Concentration Unit: mg/l)
Pollutant Control Value
Class A Class B
Monocyclic aromatic hydrocarbons
Benzene 0.005 0.05
Toluene 1 10
Polycyclic aromatic hydrocarbons
Naphthalene 0.04 0.4
Chlorinated hydrocarbons
Carbon tetrachloride 0.005 0.05
Chlorobenzene 0.1 1
Chloroform 0.1 1
Chloromethane 0.03 0.3
1,4-Dichlorobenzene 0.075 0.75
1,1-Dichloroethane 0.85 8.5
1,2-Dichloroethane 0.005 0.05
1,1-Dichloroethylene 0.007 0.07
cis-1,2-Dichloroethylene 0.07 0.7
trans-1,2-Dichloroethylene 0.1 1
2,4,5-Trichlorophenol 0.37 3.7
2,4,6-Trichlorophenol 0.01 0.1
Pentachlorophenol 0.008 0.08
Tetrachloroethylene 0.005 0.05
Trichloroethylene 0.005 0.05
Vinyl chloride 0.002 0.02
Dichloromethane 0.0050 0.050
1,1,2-Trichloroethane 0.0050 0.050
1,1,1-Trichloroethane 0.20 2.0
1,2-Dichlorobenzene 0.6 6.0
3,3’- Dichlorobenzidine 0.01 0.1
Agricultural chemicals
2,4-D 0.07 0.7
Carbofuran 0.04 0.4
Chlordane 0.002 0.02
Diazinon 0.005 0.05
Methamidophos 0.02 0.2
Paraquat 0.03 0.3
Parathion 0.022 0.22
Toxaphene 0.003 0.03
Heavy metals
As 0.05 0.5
Cd 0.005 0.05
Cr 0.05 0.5
Cu 1 10
Pb 0.01 0.1
Hg 0.002 0.02
Ni 0.1 1
Zn 5 50
In 0.07 0.7
Mo 0.07 0.7
General items
Nitrate Nitrogen(Nitrate as N) 10 100
Nitrite Nitrogen(Nitrite as N) 1 10
Fluorid (as F) 0.8 8.0
Other pollutants
Methyl tert-butyl ether,MTBE 0.1 1.0
Total Petroleum Hydrocarbons Diesel,TPH 1.0 10
Cyanide (as CN-) 0.050 0.50
Table 3 Drinking Water Source Quality Standards
Item Maximum Limit Unit
1.E. Coli 20,000(with disinfection unit)50(without disinfection unit)

MPN/100ml or CFU/100ml

2.Ammonia Nitrogen(NH3-N) 1 mg/l
3.Chemical Oxygen Demand(COD) 25 mg/l
4.Total organic carbon(TOC) 4 mg/l
5.Arsenic(As) 0.05 mg/l
6.Lead(Pb) 0.05 mg/l
7.Cadmium(Cd) 0.01 mg/l
8.Chromium(Cr) 0.05 mg/l
9.Mercury(Hg) 0.002 mg/l
10.Selenium(Se) 0.05 mg/l
Table 4 Irrigation Water Quality Standards
Item Maximum Limit
Water Temperature 35
Hydrogen Ion Concentration Index(pH) 6.0—9.0
Electrical Conductivity(EC) 750
Suspended Solids(SS) 100
Dissolved Oxygen(DO) Over 3
Chloride﹙Cl- 175
Sulfate﹙SO4-2 200
Total nitrogen﹙T-N﹚ 3.0
Anionic surfactants 5.0
Olein 5.0
Cobalt﹙Co﹚ 0.05
Copper﹙Cu﹚ 0.2
Lead﹙Pb﹚ 0.1
Lithium﹙Li﹚ 2.5
Manganese﹙Mn﹚ 0.2
Mercury﹙Hg﹚ 0.002
Molybdenum﹙Mo﹚ 0.01
Nickel﹙Ni﹚ 0.2
Selenium﹙Se﹚ 0.02
Vanadium﹙V﹚ 0.1
Zinc﹙Zn﹚ 2.0
Sodium Adsorption Ratio﹙SAR﹚ 6.0
Residual Sodium Carbonate﹙RSC﹚ 2.5
Aluminium﹙Al﹚ 5.0
Arsenic﹙As﹚ 0.05
Beryllium﹙Be﹚ 0.1
Boron﹙B﹚ 0.75
Cadmium﹙Cd﹚ 0.01
Chromium﹙Cr﹚ 0.1
Iron(Fe) 5.0
  • These Standards shall apply to irrigation water used within business areas of irrigation associations.
  • If values for determining the quality of natural water exceed the limits of these Standards, they may be exempt from the restrictions of these Standards.
  • The limits of all pollutants in these Standards are maximum limits, with the exceptions that a range is used while measuring the hydrogen ion concentration index and the lowest limit applies to the amount of dissolved oxygen.
  • All water quality items in these Standards are measured in mg/l, with the exceptions that the water temperature is in ℃; the hydrogen ion concentration index has no unit; electric conductivity is in µS/cm25℃; the sodium adsorption ratio is in √meq/l; and the residue of sodium carbonate is in meq/l.