Japan Water Systems Corporation for Reverse Osmosis Equipment (RO Equipment) and Dialysis Solution Cleaning
| 'September 1946 | Established Kobe Senpaku Shoji, |
| 'January 1948 | Renamed to The Tosho Co., Ltd. |
| 'July 1952 | Entered into a domestic sales distributor agreement with EMU in Germany for submersible water pumps. |
| 'July 1956 | Entered into a technical support agreement with EMU,Germany for submersible water pumps and executed domestic production |
| 'April 1966 | Entered into a sales and technical partnership agreement with Culligan International in USA for water treatment equipment |
| 'February 1967 | Began importing water softener system from Culligan International in USA. |
| 'January 1968 | Opened Ningyo-cho sub office to relocate water treatment division. |
| 'July 1970 | Established Domestic Division to launch water treatment business on a full scale |
| 'November 1972 | Dispatched first technical trainees to Culligan Italy and Culligan Belgium. |
| 'March 1973 | Increased capital to 40 million yen. |
| 'January 1974 | Relocated Domestic Division to Ohtemachi Sankei Building. |
| 'July 1979 | Established Hokkaido Tosho Service Co., Ltd. |
| 'September 1979 | Opened Rotterdam representative office. |
| 'October 1979 | Established a local subsidiary, Tosho (Asia) Co., Ltd. in Hong Kong. |
| 'June 1983 | Entered into partial domestic production agreement of water treatment equipment with Culligan International, USA. |
| 'March 1985 | Established Tangram Co., Ltd. ,and opened Tangram Shizuoka factory |
| 'June 1986 | Established JWS' predecessor, Tosho Machine Service Co., Ltd. |
| 'December 1986 | Opened Saipan Office ofThe Tosho Co., Ltd. |
| 'June 1988 | Entered into an agreement for domestic production of all water treatment equipment with Culligan International, USA |
| 'April 1991 | Renamed Tosho Machine Service Co., Ltd. to Japan Water Systems Corporation. Transferred all water treatment business from The Tosho Co., Ltd. (spin off) |
| 'July 1991 | Reorganized Japan Water Systems Corporation Saipan Office to the local subsidiary, Japan Water Systems CNMI Corporation and transferred all water treatment businesses. |
| 'February 1992 | Opened Japan Water Systems Corporation. Osaka Branch Hiroshima Office |
| 'August 1993 | Transferred Japan Water Systems Corporation. Headquarters to Fukagawa, Koto-ku |
| 'August 1993 | Transferred Japan Water Systems Corporation. Osaka branch to Hiroshiba-cho, Suita-shi |
| 'September 1993 | Renamed Japan Water Systems Corporation. Hiroshima office to Hiroshima sales office |
| 'August 1996 | Established Japan Water Systems Corporation local subsidiary, Island Water Systems Corporation in Guam |
| 'June 1996 | 10-year anniversary of Japan Water Systems Corporation. (June 25) |
| 'September 1996 | 50th anniversary of The Tosho Co., Ltd. |
| 'March 1997 | Japan Water Systems Corporation. Shikoku sales office became a distributor and was spun off. Established Japan Water Systems Shikoku Co.,Ltd.as a joint venture with Sanas Co., Ltd. |
| 'May 2000 | Entered into a new distributor agreement with Culligan International, USA |
| 'December 2002 | Transferred Japan Water Systems Corporation Chubu sales office to Kamiyashiro, Higashi, Nagoya. |
| 'March 2003 | Increased capital to 37.50 million yen. |
| 'July 2003 | Transferred Japan Water Systems Co., Ltd Shikoku to Kamei, Takamatsu |
| 'June 2004 | Transferred Japan Water Systems Co., Ltd Kyushu sales office to Mitoma, Higashi, Fukuoka |
| 'July 2005 | Opened Japan Water Systems Corporation Kyushu sales office Minami-Kyushu office in Kagoshima |
| 'September 2005 | Increased capital to 60 million yen. |
| 'June 2006 | 20th anniversary of Japan Water Systems Corporation (June 25) |
| 'September 2006 | 60th anniversary of The Tosho Co., Ltd. (September 9) |
| 'December 2006 | Increased capital to 98 million yen. |
| 'March 2008 | Japan Water Systems Corporation Minami-Kyushu office was transferred and opened in the city of Kagoshima as Minami-Kyushu sales office |
| 'April 2009 | Transferred Japan Water Systems Corporation Tokyo branch to Shimoniikura, Wako, Saitama |
| 'April 2009 | Transferred Japan Water Systems Corporation Osaka branch to Minamisuita, Suita, Osaka |
| 'August 2011 | Transferred Japan Water Systems Corporation Headquarters to Hachobori, Chuo-ku, Tokyo |
