Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 02, 2020	Jun. 28, 2019
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	GWRS
Entity Registrant Name	Global Water Resources, Inc.
Entity Central Index Key	0001434728
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Shell Company	false
Entity Common Stock, Shares Outstanding		22,537,381
Entity Public Float	$ 121,800,000		$ 121,800,000
Entity File Number	001-37756
Entity Tax Identification Number	90-0632193
Entity Address, Postal Zip Code	85027
Title of 12(b) Security	Common Stock, par value $0.01 per share
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Entity Addresses [Line Items]
Entity Address, Address Line One	21410 N. 19th Avenue #220
Document Information [Line Items]
Entity Incorporation, State or Country Code	DE
Document Period End Date	Dec. 31, 2019
Entity Address, City or Town	Phoenix,
Entity Address, State or Province	AZ
Document Transition Report	false
Document Annual Report	true
City Area Code	480
Local Phone Number	360-7775