A five-year study of conservation efforts, released yesterday at a Statehouse forum, proved there are things homeowners, and cities and towns, can do to relieve the stress on the Ipswich River.

But it also underscored the fact that this river's problems go further than that, and at the most, similar projects will be a literal drop in the bucket.

The core problem here is that so much water leaves the Ipswich River basin for use elsewhere and never returns, a process known as water export.

The state Department of Conservation and Recreation released the results of the study that examined the practical benefits to the river of things like lawn-watering systems tied to weather monitors that would allow sprinklers to come only when the grass really needed it.

It also looked at the water savings a homeowner could realize by collecting rainwater in a barrel and using it to water plants and lawns, rather than using water that has been treated enough to be drinkable.

And it studied saving stormwater by installing a variety of permeable surfaces, which, unlike asphalt and concrete, allow rainwater to seep through them into the ground to recharge aquifers.

The good news, said Sara Cohen, a water resources specialist with the state Department of Conservation and Recreation, is that to a greater or lesser degree, all the projects produced measurable, if mixed, water savings.

The weather-controlled sprinklers, for instance, were great for people who were profligate waterers, but actually increased use by people who were more conservative to begin with.

The study also took a look at rebates for water-conserving appliances and fixtures, such as low-flow toilets, and whether they effectively reduced water consumption. The measures worked, the study reported.

But the bad news is the Ipswich River's woes are well beyond what these measures can mend, Cohen said. They could also prove more intractable.

"I don't want to underplay the challenge," Cohen said.

Think of a water system as a sponge in a bowl full of water. You can wring all the water out of the sponge into the bowl, but if you dump the bowl onto the sponge, it's full of water again.

Wring it out anywhere else, and eventually there's no more water in the sponge.

That, environmentalists say, is what is happening in the Ipswich River basin.

From Wilmington to Salem, 330,000 people depend on the Ipswich River for drinking water. However, great numbers of those people live in Beverly and Salem, which are in the North Coastal basin.

When a Beverly resident washes clothes or flushes a toilet, the water came from the Ipswich River, but after it is used, it goes to the South Essex Sewerage District plant, where it is treated and discharged into the ocean.

A similar resident in Hamilton sends wastewater into a septic system, where it drains into the ground and eventually "recharges" the system. Even if that resident overwaters the lawn, at least the water is staying in the Ipswich basin.

"It's a tough situation," said Kerry Mackin, executive director of the nonprofit Ipswich River Watershed Association. "Especially when so many of the water rights are grandfathered."

It is also a source of frustration for local town officials, who have had to all but ban daytime outdoor water use in the summer, while Beverly and Salem have never had restrictions.

Salem and Beverly Water Supply Board representatives have long maintained they're only taking water from the river in the winter, when flows are highest and the harm done is minimal.

True, Cohen said, but the water that goes out never comes back.

"We have pretty compelling evidence that if we don't restore some of that, it won't get back to being a healthy river," Cohen said, while acknowledging any solutions are years distant.

There are massive infrastructures already in place to manage fresh and wastewater, and while septic systems do keep the water closer to home, they don't treat it.

In some arid parts of the country, such as Arizona, treated wastewater is used to water the grassy shoulders of roads. But Cohen said it takes a lot of effort to change the public perception of the practice as unhealthy.

"Change," she said, "is going to be incremental."

Mackin agreed.

"It's not an easy problem to solve to restore the river completely," she said.