How We Pulled Off the Perfect Nanny Share

When I was a few months pregnant, I bumped into my new next-door neighbor in the waiting room of our ultrasound appointments. Coincidentally, our due dates were only a month apart. "We should share a nanny!" I said, anticipating the hefty expense of child care in New York. Little did I know that it'd be one of the best decisions of our lives.

Once our daughters were born and we started our nanny share (aka one nanny simultaneously caring for kids from two different families), boundaries dissolved and we created our own type of extended family spanning two Manhattan apartments (a space the size of one deluxe master bathroom anywhere else in the country). It sounded a bit like the premise of a sitcom: two families, one nanny, hijinks ensue—except everything ran pretty smoothly in our case.

These four key takeaways from our experience may be helpful to anyone considering a nanny share.

We made a legal agreement.

Sharing a nanny turned the phrase "you can pick your friends, but you can't pick your family" on its head. As our child care overlapped, we became intimately involved with our partner family, and we learned a great deal about each other's lives. Nanny share partners don't need to be best friends, but they do need to trust, respect, and coordinate with each other every day.

Our relationship worked because we reached an agreement over almost every point involving child care. Right away, we put our arrangement in writing—a great idea, according to Jay Schulze, president of Homework Solutions, the domestic payroll company that we used. "Understanding and making sure that you and the other family are on the same page—you want to make sure that things are lined up there," says Schulze, who has years of experience working with nanny share families. "You really want some document making clear that this is the nanny share arrangement."

Some important things to consider include logistics like which home the kids will be at (will you swap weeks?), how to handle sick days and an exit from the nanny share, as well as scheduling regular check-ins between families to make sure communication is open.

As far as finding your partner family—don't sweat it if you don't have someone right across the hall. Schulze recommends finding parenting groups through social media or elsewhere online. "The best resource seems to be listservs that serve a geographic area," he says. "Those are local, so you can find families in the neighborhood. You can find one in just about every city."

We worked together to find the right nanny.

Prior to searching, my neighbor and I discussed our ideal nanny, ranging from the nanny's professional experience (we both sought someone who had cared for twins) to her working hours (our ideal schedules didn't line up precisely, so we had to compromise).

By hiring a nanny, we would become employers, which is a serious responsibility—and we needed to ensure we followed the rules. Schulze recommends that nanny share partners consult a payroll administrator to calculate salaries and understand employment laws prior to even interviewing prospective nannies. The less surprises, the better.

"You'll also need to find a nanny who is OK with working for two families," says Shulze. Not every nanny will want to be accountable to two sets of bosses, so my partner and I prioritized streamlining our approach to feel as much like "one" employer as possible. None of our legwork and organization would have mattered if we hadn't found such a wonderful nanny who embraced our sharing arrangement. (We found ours from a downtown Manhattan mom listserv—those really do work!)

We saved (some) money on child care.

In general, a nanny share costs each family less than hiring two individual nannies, but it may not always be cheaper than daycare. A Care.com survey found the average weekly rate for a nanny for one child was about $694 compared to $226 for a child care center and $221 for a family care center. (Disclosure: Care.com is a division of IAC, as is Parents.)

Since salaries and standards are different in every city, prospective nanny-sharers will need to research what they can expect to pay in their area. Some states, including Maryland, New Jersey, and Minnesota, are more affordable than others to hire a nanny, according to the survey.

I calculated our cost by taking the local market salary for a nanny to twins and splitting it evenly between our two families. Then I compared that rate to average weekly daycare rates and concluded that marginal daycare savings didn't outweigh a nanny's flexibility and convenience.

Our daughters found a bestie.

According to developmental psychologist Dona Matthews, Ph.D., our two-to-one nanny share situation drew on the best of both early child care worlds.

"If you've just got one child, then they've got another child that they're spending their day with," says Dr. Matthews. "If two families are sharing the nanny full time, you get the social benefits without the stressors of a bigger daycare situation."

Of course, not all nanny shares are idyllic. Dr. Matthews shared an anecdote involving her grandson's nanny share. "The nanny happened to really like the little girl and not like my grandson," says Dr. Matthews. Ouch. But she pointed out that such a situation could occur in any child care situation, regardless of a shared nanny.

In our daughter's case, her nanny share buddy became her de facto sister. Since the girls have been side by side from just 3 months old, they developed a close friendship that both our families hope to maintain indefinitely.

A nanny share isn't always easy, and partner families will inevitably have to make compromises—sometimes big ones. I think most of us would agree that no form of child care is perfect for everyone. Ultimately the rewards for our family far outweighed the drawbacks, and everyone in our arrangement would do it all over again.