It was the moment at Limmud when the shul came to the pool. A session at the recent festival that looked at the power of water in Jewish tradition, actually took place in the hotel swimming pool.

The location was more than a matter of novelty. The talk was part of a series intended to raise support for a new project, to open a cross-communal mikveh in North-West London, which is being led by Rabbi Miriam Berger of Finchley Reform Synagogue.

The ritual bath is a central institution in traditional Judaism. But beyond the observant Orthodox community, it has been seldom used except for conversions or pre-wedding dips. But Rabbi Berger is hoping to revive its use along the lines of a model successfully established in Boston in 2004, Mayyim Hayyim (“Living Waters”).

Halachically compliant, the Boston mikveh is used across the community, not only for the traditional reasons for immersion — such as monthly post-menstrual purification by women — but also to mark all sorts of transitions in life.

The London plan was inspired by a visit to the mikveh by Rabbi Berger herself when she was on holiday in Boston. “My husband and I had been trying to have a second child and had gone through IVF a number of times,” she explained.

“We knew we wanted to stop trying to have another child and to be happy with what we had and to accept the blessings of life as it was. I felt I wanted to mark the change and so when we were in Boston, I went to Mayyim Hayyim. For me, it was a powerful way to move from one chapter in life to another.”

When she spoke about her experience in a High Holy Day sermon at her synagogue, she was “inundated with people who told me they wanted an opportunity to mark their transitions”.

Now a campaign is under way to build a new “wellness centre”, which will include a mikveh as part of its facilities. While there is one existing non-Orthodox mikveh in the Sternberg Centre, it is small and, situated in a children’s day care centre, not the ideal location for what for users can be an intimate ceremony.

At Limmud, Rabbi Berger was joined aby Mayyim Hayyim’s education and mikveh director Lisa Berman, who explained that the Boston centre was the idea of the writer Anita Diamant, author of The Red Tent, who was researching the use of mikvaot for a book.

“The custom at the time was that there was an Orthodox mikveh that would allow non-Orthodox clergy to bring their conversion candidates one day a week,” Ms Berman said. “The clergy would bring an entire class of converts and they would stand in line in the parking lot and they would go into this tiny building where no friends or family, people to celebrate with them, could come in. It just didn’t seem like the simchah Anita felt it should be for someone joining the Jewish people.”

Mayyim Hayyim, which has two pools, now has 1,400 to 1,600 immersions a year. And what surprised the founders is that the largest group, around 35 per cent, come for the traditional ritual after menstruation. While most are women, some men come in support of their partner. Gay spouses are welcome, too.

Others use it also for traditional immersion before Shabbat or a festival. But where Mayyim Hayyim differs from a conventional mikveh is the other reasons that bring people there.“We have people who come before surgery, before the end of life, before they travel to Israel for the first time,” Ms Berman said. “There are kids who come before becoming bar or batmitzvah who think ‘This is cool’. It’s something their parents and grandparents never did, so they take on as something brand new to themselves.”

Some may come for a gender transition milestone.

While the regular liturgy contains a blessing for immersion, Mayyim Hayyim has supplemented that by producing 68 sets of readings to be used on different occasions in response to requests by users to have something to say.

“The kavannot [reflections] start in the preparation room,” Rabbi Berger says. “The sense that the preparation starts by looking at yourself in the mirror before you even go in the water is challenging, but it makes you face whatever you are there for and there is something immensely powerful in that.”

The London project, Rabbi Berger said, reflects more generally a growing focus in the Jewish community on mental health and wellbeing. The projected centre will offer a range of programming to support people in different ways. “The kind of things,” she said, “you may have run in synagogues but you have not have the numbers needed to run in individual communities — but also because that sometimes feels too close and there would be people that you know too well.

“You would be able to step outside your synagogue community and into a separate, anonymous, private space where you can simply go and be with other people in a group context or one-to-one support with mental health professionals.”

And while the estimated cost of the new building is around £3.5 million, she said, “I feel confident we’ll get this off the ground.”