Utility Plant and Intangible Assets

The following table shows Registrant’s utility plant (regulated utility plant and non-regulated utility property) by major asset class:



	AWR December 31,						GSWC December 31,
(dollars in thousands)	2018			2017			2018			2017
Water
Land	$	14,890		$	14,895		$	14,890		$	14,895
Intangible assets	29,412			29,396			29,413			29,378
Source of water supply	91,349			88,168			91,349			88,168
Pumping	182,673			178,252			182,673			178,252
Water treatment	82,198			78,999			82,198			78,999
Transmission and distribution	1,142,105			1,064,271			1,142,105			1,064,271
Other	131,419			120,820			106,907			105,246
	1,674,046			1,574,801			1,649,535			1,559,209
Electric
Transmission and distribution	82,257			76,188			82,257			76,188
Generation	12,583			12,583			12,583			12,583
Other (1)	11,224			10,955			11,224			10,955
	106,064			99,726			106,064			99,726

Less — accumulated depreciation	(561,855		)	(533,370		)	(551,244		)	(524,481		)
Construction work in progress	78,055			63,835			76,737			63,486
Net utility plant	$	1,296,310		$	1,204,992		$	1,281,092		$	1,197,940

(1) Includes intangible assets of $1.2 million for the years ended December 31, 2018 and 2017 for studies performed in association with the electricity segment of the Registrant’s operations.

As of December 31, 2018 and 2017, intangible assets consist of the following:



	Weighted Average Amortization	AWR December 31,						GSWC December 31,
(dollars in thousands)	Period	2018			2017			2018			2017
Intangible assets:
Conservation programs	3 years	$	9,486		$	9,486		$	9,486		$	9,486
Water and service rights (2)	30 years	8,695			8,695			8,124			8,124
Water planning studies	14 years	12,641			13,011			12,641			13,011
Total intangible assets		30,822			31,192			30,251			30,621
Less — accumulated amortization		(24,399		)	(23,331		)	(24,268		)	(23,221		)
Intangible assets, net of amortization		$	6,423		$	7,861		$	5,983		$	7,400

Intangible assets not subject to amortization (3)		$	422		$	422		$	404		$	404

(2) Includes intangible assets of $571,000 for contracted services included in "Other Property and Investments" on the consolidated balance sheets as of December 31, 2018 and 2017.

(3) The intangible assets not subject to amortization primarily consist of organization and consent fees.

For the years ended December 31, 2018, 2017 and 2016, amortization of intangible assets was $1.1 million, $1.5 million and $1.9 million, respectively, for both AWR and GSWC. Estimated future consolidated amortization expenses related to intangible assets for the succeeding five years are (in thousands):



	Amortization Expense
2019	$	189
2020	90
2021	12
2022	12
2023	12
Total	$	315

Asset Retirement Obligations:

The following is a reconciliation of the beginning and ending aggregate carrying amount of asset retirement obligations, which are included in “Other Credits” on the balance sheets as of December 31, 2018 and 2017:



(dollars in thousands)	GSWC
Obligation at December 31, 2016	$	4,393
Additional liabilities incurred	562
Liabilities settled	(229		)
Accretion	237
Obligation at December 31, 2017	$	4,963
Additional liabilities incurred	256
Liabilities settled	(46		)
Accretion	55
Obligation at December 31, 2018	$	5,228