Perhaps you dream of a private pier stretching out over a placid body of water -- a place where you could fish, watch the sun rise or set, and tie up your boat just steps from your door.

But why dredge up such warm-weather images just as January's chill moves in? The answer is simple: If you want your own pier or dock this summer, you need to start the process now.

For starters, it helps to define your terms. To purists, a pier is the structure built over water, used as a landing place or a walkway. A dock is actually the water next to a pier, where a boat is tied. However, those involved in regulating and building such structures use the terms interchangeably.

Whether you call it a pier or a dock, you should think about how you would like to use the structure. Do you want a simple platform where you can sip iced tea after a hectic day, or do you envision an extended walkway with electricity, boat lifts and a tiki bar?

What water depth do you need? Are you docking a Boston Whaler, a Jet Ski or a 40-foot sailboat?

"Docks are really site-specific," said John Friedman, who works in Fairfax County's Code Analysis Division.

Is your property in a flood plain or tidal wetland area? Local jurisdictions require a water quality impact assessment to demonstrate compliance with Chesapeake Bay protection laws. This includes stating how a dock will affect the aquatic life beneath it and the degree to which the shoreline might be disturbed.

Are there nesting or spawning areas nearby? That could affect what time of year construction can take place.

Will your proposed dock impede the flow of sand and silt, affecting areas downstream? Is the water prone to icing over? "Ice flow will wreak more havoc [on a dock] than boat wakes," said Chris Ragland of Mount Vernon, who has built and repaired a number of docks.

The Permit Process Despite what some people assume, permits are required to build docks. Indeed, the actual construction can take less time than navigating the approval process. And it's sometimes easier to repair or add onto an existing structure -- even if it's a wee stub -- than to get a permit for a brand-new dock. Federal, state and local jurisdictions all get involved in overseeing docks. The rules vary depending on the location and characteristics of the body of water involved.

If you're lucky, your contractor will handle the permitting process for you. If not, start with the Joint Permit Application, a document obtained through the Army Corps of Engineers on the Internet. (See box.) This multi-page form lets you avoid duplicate submissions to state and federal offices.

Eric Mays, Prince William County building official, said docks are considered an improvement to property, which means local zoning and building permits are required.

To apply for these permits, you need a copy of your property's plat and drawings of the proposed construction and placement. Piling size, soundness of walkways, and whether the dock interferes with navigation in any way will all be considered. If electricity is involved, that requires a separate permit.

Locally, one of the biggest challenges with water-oriented structures is determining where jurisdictional lines are drawn. Formerly, any structure extending into the Potomac River from Virginia's shoreline needed Maryland's approval, for instance, but that has changed. Rick Ayella of Maryland's Department of the Environment said the permitting process on the Potomac is now handled by the jurisdiction where the dock originates.

Other overlaying easements exist on the Occoquan Reservoir. There, all docks, including those originating from the Prince William County side, must go through Fairfax Water's approval process. The Occoquan Reservoir Shoreline Easement Policy contains a clear outline of the process -- in contrast with the information available from some other jurisdictions.

If you are buying waterfront property, check local regulations before completing the sale. "If you are seeking to buy property on the Occoquan to bring in your 30-foot boat, this is not the body of water for you," said Jeanne Bailey of Fairfax Water. However, the reservoir, the major source of drinking water for Northern Virginia, is a suitable place for canoes, kayaks or small fishing boats.

At the county level, Mays said that a "perfect project" without any issues will take two to six weeks for approval. The more elaborate the dock, the more time will be needed to complete the permitting. Also, the closer to warm weather, the longer the process will take because of the volume of requests.

Regulations change, so don't rely on what a neighbor who put in a dock five years ago tells you. Maryland and Virginia now limit a dock's main walkway to no more than six feet wide -- three feet in wetlands. The allowable size of the structure also varies from place to place.

Getting a Contractor Finding someone to build your dock can be harder than locating a good handyman. Dock builders are "naturally flaky watermen," said one Virginia resident who has dealt with several and who found it difficult to get phone calls returned. "Independent spirits," another called them.

However, after the remnants of Hurricane Isabel went through the region in 2003, contractors were much easier to find -- people were patrolling waters on barges and taking names of homeowners who needed repair work. It appears, though, that the storm also brought out some rogue pile drivers. Stories abound about docks that quickly sagged or were knocked off their pilings because of substandard work.

"Pilings are the weak point if not done well," said Rhonda Hunziker of United Marine Service in St. Mary's County.

Ask those who have well-built docks for recommendations, then ask the contractors how their construction techniques differ from those of their competitors. Walking a dock with a seasoned contractor is an education in itself. You quickly learn which local bodies of water have heavy ice flow; how to use angled steel beams as icebreakers; and how to minimize deterioration and maximize holding power.

For stability, stationary docks must be anchored to pilings designated for marine use. These are driven down "to the point of refusal," said Corky Sautkulis of CJS Enterprises in Dumfries, who has been building docks for 30 years. That could be eight feet or more.

Hans Hunziker, president of United Marine Service, noted the irony of requiring building permits for something in which it is impossible to inspect the most important element. You basically take it on faith that the pile drivers are setting pilings to the proper depth.

The contractor should use hardware that will withstand constant exposure to moisture. Hot-dipped galvanized steel nails and bolts are the rule. Anything less will soon rust. As concerns grow about the effect of chemically treated pilings on water quality, new plastic products appropriate for aquatic structures are continually being developed.

The best dock builders often have backlogs of several months, so be patient. You might cut the wait by going in with neighbors who also need dock work. Sautkulis said, "A good part of the cost involved is in moving the rig and equipment, so pooling customers helps keep costs down."

Fixed or Floating? The choice between fixed and floating docks is largely one of personal preference, but there are some general guidelines. Fixed docks sit higher off the water than floating docks and are preferable in places where there is a lot of current or wave action. They can also handle boat lifts.

Floating docks ride directly on the surface, rising and falling with the water level, usually via ring guides around pilings. They require fewer pilings, too -- and the ones needed are to hold the decking in place horizontally, not to support its weight. That makes repairs easier.

In addition, they're popular because of what Robert Carobrese of Sunrise Floating Docks in Davidsonville calls "butt consideration." Children and elderly people may find it easier to get into a boat from a floating dock, because instead of climbing down from a standing dock, they can just slide over on their bottoms to enter or exit the vessel.

But floating docks are not the right choice everywhere. "We discourage people from putting floating piers in very shallow water," said Ayella of the Maryland environment department. That's because they impede the flow of material underneath, disrupting the ecological equilibrium.

Conversely, "It's not wise [to have floating docks] in the brunt of the Potomac," said Hans Hunziker of United Marine. "But having a floating dock is optimal for backwater," where waves aren't a factor.

Many people use floating docks in combination with stationary ones. One popular variant is a T- shaped design, with a fixed walkway on pilings, then a ramp or steps going down to a floating platform.

There are a variety of plastic, modular floating docks, sold under names such as Jet Dock and Connect-A-Dock. These have air-filled sections that snap together building-block style, making them easy to reconfigure as needs change. Some, on rollers, can be moved ashore if severe weather threatens.

The stability of modular platforms varies greatly. In some cases, stepping on one side will cause the platform's other side to rise -- a possible dunking hazard. If you're considering a modular dock, walk on a water-borne sample before purchasing.

And watch out for tripping hazards. Some of these docks have raised connectors that can easily catch a foot.

Conventional floating docks usually have decking made of wood or polypropylene. The latter is more expensive -- more than $3 a square foot as opposed to about $1.75 for wood -- but over time requires less maintenance.

Tom and Kathy Wilson of Hallowing Point in Fairfax County chose a wood/polymer combination for the decking of their new dock. "No splinters, no maintenance, no painting," Kathy said. Their decking, basically a high-tech combination of hardwood sawdust and recycled grocery bags, costs about four times the price of wood, but the Wilsons like the reduced maintenance.

The Beauty of Simplicity On two little canals near Mount Vernon, Ragland has built or repaired most of his neighbors' small docks in his garage. "I learned how to make docks as a kid growing up in Connecticut," he said.

"I try to stay away from using a lot of hardware," he said, preferring mortise and tenon joints with wooden dowels because such construction has a longer life.

Ragland noted that docks usually disintegrate because improperly installed hardware creates a path for water.

No matter the size and shape of the dock you are building, Ragland said, "Don't take shortcuts." Get an environmental engineer to help you design the structure so it fits in with the environment. Talk to permit officials before starting the process so you can avoid surprises at the end.

"Docks start with a dream," Ragland said. "You don't want a bunch of people fueling that fire, and then have the Corps guy come in with a fire extinguisher."