When you buy a house or condo, you get, as I recently discovered, quite a number of “welcome to the neighborhood” mailings.

Most of them are from retailers — some even have some useful coupons — a few are from medical professionals and several from contractors and the like.

One came from the pastor at a local church. I chuckled, and tossed it in the wastebasket with barely a glance. Then I became intrigued and retrieved it.

If I had been in the neighborhood long, I would have been annoyed, and seen this as a proselytizing letter. It spoke of the Good Samaritan, of Jesus’ love and his assurances of “an everlasting home with our heavenly Father.” Yet, it also welcomed me to the neighborhood, invited me to services, and the pastor offered to meet with me. Good, old-fashioned neighborliness.

Meanwhile, I live within a five-mile radius of about a half dozen synagogues. No letters from them.

The National Jewish Population Survey released last fall found that only 46 percent of those Jews considered “Jewishly connected” belong to synagogues, meaning the membership among all Jews is considerably lower. With the Jewish population shrinking due both to assimilation and intermarriage, how can we not use every means at our disposal to reach fellow Jews?

I began to wonder: Do local synagogues ever send out “welcome to the neighborhood” letters, or do any type of targeted outreach? I checked with a couple dozen in Greater Washington. A couple invited me to services.

Some said they’d never thought of the idea of reaching out with a letter, and might look into it.

One liked the notion, but found it too time consuming. (Volunteers could easily help out.)

Others said it had been discussed — and dismissed (real estate agents weren’t helpful, said one; it was seen as “too pushy,” speculated another).

One Conservative synagogue has sent out about a dozen welcome letters since October, but so far hasn’t seen a response.

Of course, scouring the listings of recent home sales in search of Jewish-sounding names is risky. We’re going to miss the O’Malley who converted and the Perez who’s Sephardi, not Hispanic, and we’re going to hit a Weiss who never was Jewish and a Goldberg who married a Hansen and left Judaism behind.

But despite high rates of intermarriage, the odds remain good that when you come across a Rubin or a Goldberg or a Steinberg, it’s going to belong to a Jew.

Yes, you’ll sometimes reach someone who moved from the next town, and, like me, already belongs to a synagogue. And, yes, a non-Jew receiving the letter might be insulted, but a carefully crafted missive isn’t likely to offend.

That doesn’t seem too much of a risk to take.

Lots of Jewish organizations don’t hesitate to send fund-raising appeals to any Jewish names they can find. Charities know that most people don’t give if someone doesn’t ask them. And many organizations are exceedingly good about follow-up.

Don’t forget the old joke about the businessmen stranded on a desert island. No one can understand why one remains so calm, confident the group will be found. “Don’t worry,” he says. “I haven’t paid my UJA pledge yet.’

Yet, synagogues remain timid about outreach, perhaps in part due to fears of being seen as proselytizing.

Plus, Orthodox shuls may feel no need to reach out. It’s the rare Orthodox person who will move to a neighborhood without checking out the area shuls in advance.

Yet it’s not uncommon for other synagogues to draw members living in a five- or even 10-mile radius. And, it’s not unusual for people new to an area to shul-shop.

Some Jews, however — especially those who never belonged to a synagogue, or who haven’t set foot in a shul since their own bar or bat mitzvah services — feel intimidated to walk into a new synagogue for a Shabbat service, or might never even think about it if not invited.

Instead of just announcing a prospective members’ tea in the local papers, why aren’t our synagogues reaching out to new people in the community and extending a welcome? Why not invite newcomers to a Shabbat dinner or lunch with the rabbi, cantor or one of the officers? Don’t talk about membership; just invite them to be with you.

Don’t stop with new home buyers. Contact local campus Hillels to learn which graduating seniors plan to remain in the area, and reach out to them as well.

We are taught to fulfill the mitzvah of hachnasat orchim, welcoming guests. Abraham and Sarah kept their tent open on four sides to make sure guests always knew they were accepted in their home.

Despite the burgeoning numbers at some of our synagogues, we continue to see increasing numbers of unaffiliated Jews. Many will never walk in unless asked. We must more than welcome guests, we must actively seek them.

A simple letter can let a newcomer know that the congregation’s tent, its sanctuary, is open. That individual just might walk in the door — and soon be not a guest, but at home as part of your synagogue family and as part of klal Yisrael, the larger Jewish community.

Debra Rubin is editor of Washington Jewish Week, and a past president of the American Jewish Press Association.