B.F. Mahn & Sons

B.F. Mahn & Sons B. F. Mahn & Sons, Inc in De Soto, MO provides a range of HVAC and plumbing services across Jefferson County. Clair, and Fenton in neighboring areas. J.P.

We are certified licensed plumbing and mechanical contractors and are associated with the Better Business Bureau and the NFIB. Our company is bonded and insured, so you can feel good about trusting us with your plumbing, heating, or cooling needs. Our company has been family-owned and operated since 1868, and is currently run by Bernard F. “Biff” Mahn III and his sister Beth (Mahn) Ross of De Soto

. The company still operates out of the same two-story brick building where their great-great-grandfather was recorded as a blacksmith in 1868. The family believes it is the oldest business still operating in DeSoto, family or otherwise, and is proud to not only carry on their family's name, but provide excellent service to Jefferson County communities including: DeSoto, Festus, Hillsboro, Crystal City, Grubville, Dittmer,, Arnold, Barnhart, Herculaneum, High Ridge, House Springs, Imperial, Lonedell, Hematite, Mapaville and Cadet, Richwoods, St. Mahn & Sons, Inc began as a horse and carriage blacksmith shop with no formal name operated by John Kempe. Kempe's blacksmithing business continued into the second generation with his son, Henry Kempe. Henry's daughter, Mildred, married Bernard F. "Dutch" Mahn, who expanded his in-laws' operation in the 1920s. Dutch started a tinsmithing shop on the upper floor, where he did gutters, roofs and stovepipes. For a little over a decade, both business thrived, blacksmith on street level and tinsmith on upper level. By the mid 1930's, even the largely rural, horse-and-buggy town of DeSoto, was going mobile as automotives became the transportation of choice, and the need for blacksmithing services faded. The family restructured the business plan to advance with the changing times. As an innovative entrepreneur, Dutch Mahn led the area in a new direction with the advancement of indoor plumbing and heating technologies. Phillip “Phil” William Mahn and Bernard F. “Bernie” Mahn, Jr. were next in line to continue the legacy in the 1950’s. Bernie ran and expanded the thriving business while Phil continued with the plumbing and tinsmith skills. Biff Mahn’s own introduction into the business came at a tender age of 10. He began holding flashlights for the men and sometimes getting into crawl spaces, in between floor joists or anywhere else the bigger guys couldn’t fit. He didn’t collect a dime but gained priceless knowledge. He began earning a paycheck during high school, working summers as a plumber’s apprentice. He’s been there ever since. Beth (Mahn) Ross started working summers when she was 15, but unlike her brother, she didn’t come back into the family business as an equal collaborator until 1993 when Bernie was forced into early retirement due to failing health. Beth stepped into her father’s shoes, running the business and continues as a respected leader in the community. The next generation has been launched at B. Mahn & Sons, Inc. Jonathan “J.P.” Mahn has put on the uniform in the image of the exceptional men before him. attended the local college to gain his certification. His education, his determination and his natural ability will take us into the future…

B. is here today – and will be tomorrow. Our current staff is:
B. "Biff" Mahn, III
Beth (Mahn) Ross
Jonathan "J.P." Mahn
Danny Lewis
Brian Scott
Pat Youngman

Trusted Plumbing & Heating Services in Jefferson County Since 1868
For over 145 years, B. has provided plumbing and HVAC services in De Soto, MO and surrounding areas. We are proud to be family-owned and operated, and work hard to treat every client like family. For more information about our plumbing, heating, cooling, or bathroom remodeling services, please give us a call at (636) 586-2300 or fill out a contact form.

THANK YOU, JEFFERSON COUNTY! We are incredibly honored to be voted:Best Plumbing CompanyBest Heating & Cooling Company— ...
06/01/2026

THANK YOU, JEFFERSON COUNTY!

We are incredibly honored to be voted:
Best Plumbing Company
Best Heating & Cooling Company

— TWO YEARS IN A ROW! —

From our family and team at B. F. Mahn & Sons, Inc., thank you for your continued trust, support, and votes. Serving this community since 1868 has been an honor, and we are grateful to continue serving the people and businesses that make Jefferson County such a great place to live and work.

Congratulations to all of the winners and finalists! The local businesses and residents of Jefferson County are what make this community so special.

A special thank you to Leader Publications for hosting this year’s Best of Jefferson County Awards.

05/30/2026
Today, we remember and honor the brave men and women who made the ultimate sacrifice for our country and our freedom. 🇺🇸...
05/25/2026

Today, we remember and honor the brave men and women who made the ultimate sacrifice for our country and our freedom. 🇺🇸

Memorial Day is more than a long weekend — it is a time to reflect on the courage, selflessness, and dedication of those who gave everything while serving our nation.

From all of us at B.F. Mahn & Sons, Inc., we extend our deepest gratitude to the fallen heroes and their families. Your sacrifice will never be forgotten.

As we spend time with family and friends today, may we pause to remember the true meaning of this day.

God Bless America. ❤️🤍💙

B. F. Mahn & Sons, Inc. has been nominated again for Best of Jefferson County in BOTH Plumbing and Heating & Cooling! 🏆🔧...
05/16/2026

B. F. Mahn & Sons, Inc. has been nominated again for Best of Jefferson County in BOTH Plumbing and Heating & Cooling! 🏆🔧❄️🔥

We are beyond thankful for the continued support from our amazing customers, friends, family, and community. Winning last year meant so much to our entire team, and we would be honored to earn your vote again this year!

✅ You can vote ONCE PER DAY
✅ Voting only takes a minute
✅ Every vote truly helps our family business

Please click the link below and vote for B. F. Mahn & Sons, Inc. in BOTH categories:

https://myleaderpaper.revfluent.com/bestof/og/ko483mzlg1/jp7jxjxnvd

Thank you for trusting our team since 1868. We appreciate each and every one of you! ❤️

Vote in any or all categories once per day April 30th through May 17th CDT! Choose wisely! Votes are locked-in and can not be changed after 10 minutes. For your votes to be counted, make sure to vote in at least 5 categories.

Congratulations to the De Soto Senior High School Class of 2026! 🎓What an incredible accomplishment! We are so proud of ...
05/15/2026

Congratulations to the De Soto Senior High School Class of 2026! 🎓

What an incredible accomplishment! We are so proud of these students and all of their hard work, dedication, and bright futures ahead.

B. F. Mahn & Sons, Inc. was honored to be a part of Scholarship Night and to award a scholarship to a deserving senior from our community. Investing in the next generation is something we deeply believe in, and we can’t wait to see all the amazing things these students accomplish.

We also want to congratulate ALL 2026 graduates as they celebrate this huge milestone. Whether your next step is college, trade school, military service, or entering the workforce, we wish you success and blessings in the journey ahead. Your future is bright! 💚🤍🖤

04/27/2026

Big congratulations to Cole Beckler!
1st in the state for SkillsUSA HVACR — an incredible accomplishment.
We’re proud to have you on the B. F. Mahn team and can’t wait to see you compete at Nationals. Go get ’em!

04/27/2026
We may fix furnaces, water heaters, and plumbing problems…But what really warms our hearts is what YOU say about us ❤️Th...
02/14/2026

We may fix furnaces, water heaters, and plumbing problems…
But what really warms our hearts is what YOU say about us ❤️

This Valentine’s Day, we’re celebrating the love we feel from our customers through your Google reviews. Thank you for trusting B.F. Mahn & Sons to take care of your homes.

Quality service since 1868 — and grateful every day.

https://share.google/Drr4Oj8pbrWwKr4NS

Address

112 West Clement Street
Desoto, MO
63020

Opening Hours

Monday 8am - 5pm
Tuesday 8am - 5pm
Wednesday 8am - 5pm
Thursday 8am - 5pm
Friday 8am - 5pm

Telephone

+16365862300

Alerts

Be the first to know and let us send you an email when B.F. Mahn & Sons posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Contact The Business

Send a message to B.F. Mahn & Sons:

Share