SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Part 4 (Details) - USD ($)				12 Months Ended
	May 06, 2020	May 08, 2019	May 02, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 09, 2015
Stock Compensation Plans [Abstract]
Granted (in shares)				0	0	0
Compensation costs				$ 178,000	$ 181,000	$ 192,000
Unrecognized expense related to non-vested awards of restricted shares granted				59,900
Accounts Receivable [Abstract]
Increase in reserve for bad debt				500,000
Expense related to allowance for doubtful accounts				800,000	200,000
Summary of changes in entity's accounts receivable [Abstract]
Gross accounts receivable				11,024,000	7,177,000
Less allowance for doubtful accounts				862,000	264,000
Total Accounts Receivable				10,162,000	6,913,000
Summary of allowance for doubtful accounts [Abstract]
Beginning balance				264,000	232,000
Allowance adjustments				754,000	198,000
Recoveries				13,000	34,000
Write off of uncollectible accounts				(169,000)	(200,000)
Ending balance				$ 862,000	264,000	232,000
Cash and Cash Equivalents [Abstract]
Maximum maturity period of temporary cash investments considered as cash equivalents				3 months
Maryland [Member]
Use of Estimates in the Preparation of Consolidated Financial Statements [Abstract]
Payment arrangement minimum term				12 months
Delaware [Member]
Use of Estimates in the Preparation of Consolidated Financial Statements [Abstract]
Payment arrangement minimum term				4 months
Restricted Stock [Member]
Stock Compensation Plans [Abstract]
Compensation costs				$ 178,000	181,000	$ 192,000
Customer accounts receivable - water [Member]
Summary of changes in entity's accounts receivable [Abstract]
Gross accounts receivable				6,707,000	5,574,000
Customer accounts receivable - wastewater [Member]
Summary of changes in entity's accounts receivable [Abstract]
Gross accounts receivable				1,717,000	209,000
Miscellaneous accounts receivable [Member]
Summary of changes in entity's accounts receivable [Abstract]
Gross accounts receivable				699,000	402,000
CIAC receivable [Member]
Summary of changes in entity's accounts receivable [Abstract]
Gross accounts receivable				$ 1,901,000	$ 992,000
Class A Stock [Member] | 2015 Equity Compensation Plan [Member]
Stock Compensation Plans [Abstract]
Number of share authorize under equity compensation plan (in shares)							331,500
Class A Stock [Member] | Restricted Stock [Member]
Stock Compensation Plans [Abstract]
Granted, restricted stock awards (in shares)	5,000	5,000	5,000
Fair market value (in dollars per share)	$ 35.01	$ 36.11	$ 38.51